This is gonna be a good fuckin' festival, man!" bellows Marco Rea; and it will be, not least because we are getting his band, The Marbles, out of the way early on. Rea's frankly alarming Charlie's Angels bouffant is the most striking thing about them, and probably the most modern: it only dates back twenty years, while their widdly-widdly-bwanggg! rock-god fantasias and songwriting fresh from the clichi-o-mat, on the other hand (sample lyrics: "Stop draggin' me down," "Such a big star," etc) are definitely from the wrong end of the 1970s. On the brighter side, two actual seventies covers near the end are actually quite juicily brilliant. A career as The Black Crowes Experience awaits.

A miracle cure for grey skies and greyer predictability, then, arrives in the form of inscrutable Galwegians Cane 141. Simultaneously buttoned-up and boffinish (spectacles count: 5 musicians out of 7) and with a chilly Warholian veneer of Factory-cool and theatricality, they complicate matters by being charmingly overemotional, lovingly detail-obsessed, human-sized. Broad dreamy canvases are stretched to hold all manner of lovely minutiae: lonely pinging waveforms out of Broadcast, smouldering Tinder-sticky snare shuffling, sighing Bacharach trumpet... and we're suddenly very excited about being at Witnness.

But relax: we are, as the saying goes, at our auntie's. If Badly Drawn Boy was any more affable, he'd actually be handing out cups of tea to everybody here. Probably the most anticipated artist at Witnness, Damon reacts by being chatty, random-access and utterly unprepared - that is, if you don't count crap practical jokes so meticulously orchestrated you can still smell the midnight oil.

When the songs finally come, they are fractured, half-life incarnations, not remotely as fully realised as on that stunning debut album, all missing verses and false starts.

Inexplicably, it doesn't matter. As he bounds into the audience during 'Pissing in the Wind' for a geek-oid press-the-flesh harmonica opportunity, or falls repeatedly to his knees before a monitor during 'Another Pearl' with a spectacular lack of irony, you realise that you wouldn't have him any other way. And even in their half-assembled state, the songs themselves knock nearly everything else we hear today - guilelessly, charmingly, beautifully - into a stripey woollen cocked hat.

From innocence, then, to world-weary experience: the world is too much with Doves. Squandered opportunities are mournfully picked over and youthful folly soberly re-visited within songs as heavily ornate and breathtakingly massive as cathedrals, and just as sombrely beautiful. This isn't gothic doom-peddling, however: their swirling melancholia always pulls us safely through to grown-up pop transcendence, triumphant and unbowed, in the end. If they've seen the gutter, they're certainly more interested now in showing us where to look for the stars.

Over on the main stage, Jack L is bringing decadent glamour to a big, wet racecourse. Jack has the voice and the showmanship for sure, but whether it all adds up to much is questionable. 'Brilliant,' say some. 'Average cabaret,' say others.

If Feargal Sharkey's a hard act to follow, no one's bothered telling Paul McLoon who this afternoon looks like he's been fronting The Undertones all his life. Having sensibly decided not to write any new material, the band deliver a no-frills Greatest Hits set, which peaks with a gloriously edgy 'True Confessions'. The obvious reservations aside - 'Teenage Kicks' is not supposed to be played by a bunch of fortysomethings - it's perfect festival fare.

The only way you could've enjoyed the Happy Mondays is if you were off as your face as they were. With Shaun Ryder doing his performing drunk routine, and the rest of the band looking like they'd rather be at home, this really was fag-end stuff. Time gentlemen, please!

In this country, where you are issued a copy of White Ladder along with your passport, David Gray wouldn't have had to do much to carry off tonight's headline slot other than turn up, waggle the head about a bit and go home. So how very nice of him to give a performance of an emotional depth and magnitude we haven't seen since his 'David who?' days in Whelans.

'Please Forgive Me' and 'Babylon' - made fashionably over-thin on White Ladder by those tinny, palpitating beats (not to mention tediously ubiquitous at this point) - are, tonight, different and fascinating creatures entirely. The beats are still there, but they add interesting textures rather than definition: and so they're delightfully breathy, randy, full of life and a run-away-with-me voluptuousness.

He gives us a searing rendition of oldie 'What Are You', a full-on reel through old-skool ecstatic romanticism, positively incandescent with raw desire and, I'm sorry, righteousness. We thought he gave that kind of thing up when Donal Dineen left No Disco.

"Fuckin' 'ell, I'm a rock star!" David giggles to a (predictably) rapturous reception, half joking, totally gobsmacked. Never mind that, surely the point is: fuckin'ell, that was brilliant.

Leftfield take to the main stage at 11.30. Even though Rhythm And Stealth has failed to enrapture as many devotees as their classic debut Leftism, they demonstrate live just how dub/techno/electronica in 2000 should sound.

Deep, tribal and imbued with a soulful emotion that is sorely lacking in the world of superclubs and superstar DJs, MC Chesire Cat (sadly missed at Homelands) is the perfect frontman to bring Barnes and Daley's bruising sounds to the largest of festival arenas.

During an epic fifteen-minute rendering of Leftism favourite 'Inspection Check One', they attempt a build-up that is almost dangerously long, but instead sends an awestruck crowd into spasms of delight. 'Afrika Shox' has the most terrifying vocodered vocal since 'Stuka' on Primal Scream's Vanishing Point, and from there they segue into the melodic beauty of 'Song Of Life'.

Just as a reminder that Leftfield reside within the world's elite of electronic composers, they leave Witnness with the monumental parting glass of 'Phat Planet'. It begins as low rumble, but by the four-minute mark, thousands can barely take it.

Its monstrous crescendo grinds to a halt and MC Chesire Cat roars slowly at the crowd - "YOU ARE THE BEST!" All four of Leftfield are standing upright, hands held aloft. For just a moment, they look like a punk band. More performances of this calibre and they'll be regarded as an entity even more important than one.

SUNDAY

"Are we happy to be here or what?" breathes Gary Lightbody out of Snow Patrol. Our sentiments exactly: indeed, even during their shouted-down quieter numbers (in a rare contemplative Snow moment, some wag yells: "Rock festival!!") they get one of the best receptions of the weekend.

Resistance is useless. You can lead your intellectualism - your art-school, subtlety-spotting Belle-and-Sebastian inclinations - to water, but you can't make it drink when what it wants to do is jump up and down incoherently to Wilt. They will take home no prizes for originality of thought or approach (unless they are carrying them home as a favour for obvious heroes Husker Du, Foo Fighters and Green Day) but today, their songs come out blazing - summer pirate-radio anthems to a man - and it sounds bloody wonderful.

Groove Armada reveal that there are far more strings to their summery bow than nicely strung out set pieces. Material from the Vertigo album is far too plain and basic to really do the business in the mid-afternoon slot, but it is the previews from their forthcoming opus that really clinch it. These are harder, darker and throbbing with a harmonic tension that their work to date has sorely lacked.

Having managed to tear themselves away from The Met Bar, All Saints deliver a Crufts-winning dog of a set, which doesn't even work as a piece of highly choreographed pop. Looking, and sounding, thoroughly bored, the group reach new levels of awfulness with their cover of Run DMC's 'Walk This Way'. It's going to take one hell of a second album to buy them a career extension.

Meanwhile, the strappy-top-and-aviator-sunglasses spectre of All Saints, playing simultaneously on the main stage, hangs like a designer pall over those of us who have opted instead to swop quiet tales of city sickness with Jubilee Allstars. "Thanks for being here," Barry murmurs, before adding: "I know where I'd be." A few plaintive, slowly unspooling moments of subdued, countrified brilliance apart, their frustratingly underwhelming set - full of great songs stuck helplessly down cul-de-sacs - suggests that he may know something we don't. Greatness beckons, clearly but from quite far away.

Mind you, playing the main stage isn't all fizzy orange and tea cakes either. Embrace, for example, display what can happen when you amplify your mild-mannered epiphanies for the masses: in this broad-stroke, singalonga context, it just sounds like one colourless, beery student anthem after another.

Back we flee, then, to the man with the antidote. While, sadly, an accompanying clarinet is near-indistinguishable and an over-imperative bass end is too audible by half, David Kitt's patient beat-box cadences and pastel-box melodies shine radiantly through, each miniature drama heightening and ebbing in pleasingly small increments and in all the right places. And then there's wee Robbie, The Brother, a half-size Liam Gallagher-in-waiting who lends his high piping voice in a festival-beating highlight. "Y'alright?" he addresses us coolly, cocking his head, the Kitt family rock-n-roll gene made tinily manifest, albeit having evidently skipped a sibling.

Roni Size and Reprazent are undoubtedly one of the best live prospects that drum n' bass can offer. The relentless energy of their eight-piece line up kicks out the jams in a way that d 'n' b should but rarely does. Live drumming and bass guide the whacked-out grooves to harder, more pulverising extremes than Reprazent's rather dull and doodly records. 'Brown Paper Bag' gets its obligatory airing, and predictably the place goes ga-ga. While a fine job is done sustaining the energy and pace of the set, some segments are dreadfully samey.

You know you're at a festival when the perennially-seated David Odlum out of The Frames, a poker-faced one-man campaign keeping chairs safe for rock'n'roll, delivers his tightly-focused pyrotechnics (and quite animatedly, too!) from a standing position.

That's not the only Witnnessed difference: tonight, their endlessly sparking and unpredictable off-beat poetry is wearing not its heart, but subtlety-be-damned go-faster stripes on its sleeve. Probably wisely, too: anything too complicated or elusive would have been rendered invisible in the glare of tonight's jizzed-up marquee. It's all good. Still, it makes you long for those grand long stretches in the evening in Dublin, where they have proper time and space, and effortlessly evoke one-time-only, glittering magic on a regular basis.

Ira Kaplan and Georgia Hubley out of Yo La Tengo, possibly the Rock "Celebrity" Couple least likely to ever be given a photo spread in HELLO!, nonetheless quietly invite us into their home tonight to pore over intimate snapshots from their own courtship and marriage, subtly framed by Georgia on drums and sung by Ira at pillow-whisper volume. It's an entrancing and lovely experience, not to say quite brave of them. As always, Ira is also endlessly capable of railing, destructive guitar masochism.

The highlight, however, is definitely the cover of sweet Fifties-housewife ditty 'You Can Have It All', sung by Georgia in her wallflower hush and with Ira and bassist James on hilariously earnest rhumba-and-hand-gestures detail, looking not unlike two lumbering but impressively well-trained dancing bears. Now that's entertainment!

Past their sell-by date? Bollocks. They may be entering their second decade as a band, but there are no signs of tiredness or complacency as Therapy? show the youngsters how it's done on the More stage. So what if Andy Cairns is looking increasingly like your Dad wearing a leather jacket? - the hour-long mix of hits and new songs from Suicide Pact... demonstrates that they're as relevant now as they were in1989.

Talking beforehand to hotpress, Beck had said that he was in the mood for a party, and sure enough, this was dancing-on-the-ceiling sort of stuff.

Unrecognisable from the mumbling slacker-type who first played here 10 years ago, the boy Hansen works the stage like Steven Tyler, except with infinitely better dress sense. With an army of people on stage with him, the set has the air of a Y2K soul revue.

Tossing away his best-known song, 'Loser', in the first 10 minutes is a brave move, but one that doesn't backfire as the likes of 'Sexx Laws' and 'Devil's Haircut' prompt an even more frenzied response. The David Gray brigade may disagree, but for my money, this was the highlight of the weekend.

As for Travis . . .well, they're Travis: melodic and pleasant, but lacking anything resembling power or originality. All the hits are here, as is the now-famous cover of Britney's 'Baby One More Time'. The band play well, Fran sings well and it's all very nice but very uninspired. Travis can't shake off the impression that they're Britain's luckiest band.

As the festival wends its way towards a conclusion, ASIAN DUB DOUNDATION wow Witnness More. The rhythms are tight, the music potent, and the punters go understandably mental. A heaving, dancing mass with a political conscience. Now, there's a concept.

Additonal reporting: Stuart Clark, Niall Stanage, Eamon Sweeney

HAPPINNESS!

The best of the fest!

* Huge luminous white balloons that look like the moon - a gorgeous detail for two gorgeous nights.

* Hats - Damon Gough's tea-cosy. Cane 141's Michael Smalle as cowboy manque. Glen Hansard's black bank-heist woolly. All the best pop stars have 'em, you know.

* Robbie Kitt - all stand and uncover for Dublin's newest rock minigod.

* Bizarre homemade banners and signs - "Please help me find ecstasy, acid and potatoes" was our favourite.

* Badly Drawn Boy - he just was, alright?

* Portaloos labelled "Wee-nness?" - hee hee hee. Admit it, you laughed.

* Inflatable couches - home is where your arse is.

* Loads of Irish acts on the bill - a decent festival gigs for deserving locals, without having to enter competitions, support proper bands or be The Cranberries. Not before time.

* The weather - relatively dry all weekend, and sunny on Sunday! Hurrah.

SADNNESS!

and the less good bits

* Closing the bar at 10pm on Sunday - what?! But Travis aren't finishing for another hour and a h... oh, never mind.

* Portaloos that remind you of that scene in Trainspotting - would it kill you to hire people to look after them? No, it wouldn't.

* People who lie down randomly in the middle of nowhere - if you wanted us to step on you, you eejits, all you had to do was ask.

* The perennial Hothouse Flowers on the 'Rising' stage? - why not just put The Undertones on in there and be done with it?

* There's no camping. Yes there is. No there isn't - clearer instructions next time please. Not all of us can drive home in our Mercs.