While almost everyone is in agreement that day three is the strongest of Pitchfork 2010, it started out on the main stages with only slightly more energy than the past two days.

To be clear, I have nothing against chill-out music as a genre; I just expect ambient pop to measure up to the best of what I’ve heard from that sound in the past, whether it’s the godfather himself, Brian Eno, or Aphex Twin in his ambient mode, or the mellower of the early ’90s shoegazers. Too much chillwave, doesn’t rise to those peaks on record. And even if it did, that’s not guarantee that it can carry a crowd of 18,000 in the festival setting. Especially when it’s interspersed with just plain generically jangly indie rock.

Kicking things off on Sunday, not long after a heavy rain yielded to plain old oppressive heat and humidity, Chicago’s Allá gave the crowd a taste of chill sounds at their best, with singer Lupe Martinez cooing seductively as the musical team of brothers Jorge and Angel Ledezma created lush pillows of sound and gently percolating, occasionally Latin-flavored grooves behind her.

At his mellowest, California-bred singer-songwriter Cass McCombs brings to mind a less polished Lloyd Cole; at his best, which is very good indeed, things tip more toward garage rock and Paul Westerberg. During the second main-stage set of the day, McCombs gave a taste of both, drawing from his fourth album “Catacombs” (2009), as well as dipping deeper into his back catalog for a strong if never really fiery set.

Girls, unfortunately, were another step back toward mid-tempo mediocrity. The twee, tinkley sounds seem so fragile that merely listening too hard might cause them to fall apart—though the precious mix of the floweriest San Francisco circa ’67s psychedelia and mellowest Smiths isn’t helped by the lack of charisma evinced by bandleaders Christopher Owens and J.R. White. Gotta say, I would have loved to have heard another set from Allá instead.

By mid-afternoon, it was time for more mellow as Beach House, the ethereal duo of Victoria Legrand and Alex Scally, played a wispy, dreamy set of songs that functioned as intimate pillow talk—that just happened to be overhead by 18,000 people.

“You know, as headphones music, this stuff is great,” said one concertgoer standing beside me during the Beach House set. “But here… now… really?” My thoughts exactly, and obviously expressed not for the first time during this long, somnambulistic weekend.

Thankfully—finally!—there was a welcome shot of adrenaline from the next main-stage act, the aptly named Lightning Bolt from Providence, Rhode Island. The earth-shaking, cascading rhythmic assaults of drummer and vocalist Brian Chippendale (he had one of those headset microphones hidden beneath his Lucha Libre mark) and bassist Brian Gibson were so powerful and overwhelming that it was hard to fathom that they were being churned out by only two guys—and both named Brian, no less.

The churling, co-ed mosh pit in front of the stage erupted during the first notes of Lightning Bolt’s set, and it never let up. Clearly, at least some of the crowd filling Union Park was as eager for an outlet for their adrenaline as I have been.

Alas, things soon calmed down again with St. Vincent. With the temperature decreasing ever so slightly and the sun finally setting—though it had been obscured by clouds anyway for much of the day, anyway, with the threatened thunderstorms thankfully holding off—Annie Clark and a sizable band lilted through the songs she prefers to think of as mini-film scores, with lush orchestral pop arrangements and frequent hints of naïve and childlike touches straight from vintage Disney soundtracks.

It was charming. It was enchanting. But it was hardly revelatory or mind-blowing. And no, I ain’t jaded, and yes, I still love Pitchfork. But where in 2010 were the sort of shear-the-top-of-your-head-off experiences like Art Brut, Os Mutantes, and Mission of Burma (2006), Clipse, Girl Talk, Mastodon, and Battles (2007), Les Savvy Fav, Titus Andronicus, and F— Buttons (2008), or F*cked Up, Ponytail, and the Vivian Girls (2009)?

In way too short supply, that’s where.

(photo by Kate Gardiner/NewsHour)

The tempo picked up again with Major Lazer at 6:15 p.m., and — hallelujah! — it stayed at a pretty high level through the end of Pitchfork 2010.

Major Lazer (photo by Kate Gardiner/NewsHour)

During Major Lazer’s set, the field in front of the main stages became one undulating mass of sweaty bodies gyrating to the globe-spanning grooves of DJs and producers Diplo and Switch, augmented by assorted dancers, partiers, posse members, and giant Chinese puppets. The Jamaican dancehall rhythms that form the basis of the duo’s album “Guns Don’t Kill People — Lazers Do” were at the heart of the live set, too, though there are so many more ingredients in the mix that the sound is best described as a mash-up of a hundred of the best dance stations on earth, all received simultaneously through outer space, laid on top of one another, and remixed by a crazy stoner alien who’s happened to set up a home studio on Venus.

There ain’t no party like a Major Lazer party, and the Major Lazer party don’t stop. (If only more of Pitchfork ‘10 had been like this!)

Big Boi (photo by Kate Gardiner/NewsHour)

As the penultimate act of the day and of the festival, moonlighting Outkast emcee Big Boi also brought the funk, delivering the challenging but tuneful genre-mashing sounds of his recent solo album “Sir Lucious Left Foot: The Son Of Chico Dusty” onstage‚  with maximum energy and minimal trite hip-hop crowd-baiting tomfoolery (though he did pause once to ask the honies in the house to, er, show him their mammary glands, a request to which no one in Pitchfork nation responded — and no, I would not count the dudes without shirts that my colleague Justin Kaufmann has been chronicling).

Adding to the videos that provided most of the visual appeal of Big Boi’s set, the rapper was joined by the same local troupe of young breakdancers who earlier adorned the stage as Raekwon performed.

Then, at last, it was time for the final set of the weekend — but not before a bit of priceless comedy courtesy of “Rockin’ Rian Murphy,” who claimed to have been a DJ on Q101 during the early ’90s heyday of alternative rock, but who in fact is the wickedly satirical co-founder of Pavement’s original label, Chicago’s Drag City.

Pavement always had an uneasy relationship with the corporate feeding frenzy that followed in the wake of Nirvana’s “Nevermind,” though that did not stop the group from, say, courting modern-rock radio play with its middle and later-period singles, or performing as part of the original touring Lollapalooza (much to the chagrin of the band’s nemeses, the Smashing Pumpkins, in what passed as rock’s answer to the Tupac/Biggie feud back then).

Murphy brought the silliest aspects of those days flooding back as he bemoaned his inability to “break” the band during his (non-existent) days as a Q101 “personality,” and the more the crowd shouted for him to shut up and let Pavement play, the more he rambled on, with the anger on the field palpably building. It was amazing, really, how few people “got it”—and it was just as surprising that a considerable number of the under-25 fans began leaving midway through Pavement’s set, which turned out to be much better than I expected.

Having caught the band several times in its earliest days with drummer Gary Young, a middle-aged (at the time) drunk who spent as much time running around in the crowd as he did behind his drum kit, I always considered that to be the ultimate live Pavement. The other musicians could be shoegazers, and at least Young offered a bit of silly visual excitement. Mid-period Pavement was fine musically but offered little to look at, and the late period of the band was marked by the occasional pointless noodling.

Though Young is missing from the reunion, Stephen Malkmus and his bandmates were musically concise, tight, and focused, and they delivered many of their best songs—“Range Life,” “Frontwards,” “Greenlander,” and “Unfair” among them—in versions that were every bit as strong as they were back in the day, and better in some cases than that last stage of the group. Since the music always seemed timeless, there was less of a taint of nostalgia here then with, say, the Pixies reunion, though to be sure, the motivations probably were very much the same, and mostly colored green.

So that was that for the fifth (or sixth) Pitchfork Music Festival, and the one—and I trust you’ve gathered this by now—that I liked the least. But I do need to make one more thing very clear: The festival consistently remains the best-run, most community-oriented of any of the (conservatively) four dozen of these sorts of events that I’ve attended across the country and in Europe over the last three decades.

Pitchfork is the festival Chicago needs and deserves. So it had an off year; that doesn’t mean I’m not already looking forward to 2011. And even a mediocre Pitchfork will always be infinitely better than the soulless and corporate Walmart on the Lake known as Lollapalooza–which, as my recent reporting hopefully has made clear, is a very Chicago event in all of the worst ways, while Pitchfork continues to stand for the local music community at its best.