iHeartRadio Music Festival Las Vegas: Black Eyed Peas, Kelly Clarkson, Alicia Keys, Jay-Z perform

When you think about it, there's really only one way to kick off a pop music festival: with the gyrating, electro, pulsing sounds of the Black Eyed Peas, of course.

The foursome opened the iHeartRadio Music Festival at the MGM Grand Garden Arena last night with laser lights, a cadre of jailbird-themed backup dancers (in a word: divine), and one of their signature songs, "Boom Boom Pow."

It's almost needless to say, but the party-rocking vibe the show's producers were no doubt hoping for coalesced perfectly, as the crowd spiraled into dancing through songs like "Just Can't Get Enough," "Don't Stop the Party," "The Time (Dirty Bit)," and the perfect set-ender: "I Gotta Feeling." (Personally, I was hoping for "Shut Up," but no one ever seems to be into that song as much as me.)

Of much interest — at least to me — was Fergie's delightful getup, which included glittery knee-high boots and onesie, and fascinating, gold fingernail/cap things that contributed to her overall drag queen look. She was Vegas to a T! (Then again, she always kind of is.)

The tone was set from the first act: This show was definitely all about the hits, and the 12,000 fans in the audience at the MGM Grand Garden Arena seemed to get just what they wanted. From top to bottom, the show was quite the Vegas production with huge screens flanking the stage, more than one confetti blast (the first one came at the almost-still-daylight time of 8:01 p.m., no joke), and, yes, Ryan Seacrest as host.

He first appeared after the Black Eyed Peas left the stage to introduce the show: "This weekend," he said, in a trademark way that's both overly dramatic and overly bombastic, "all roads lead to Vegas." Well, all roads carrying the biggest pop stars, at least. And it was during this interlude that he announced something that made the crowd go completely wild: Lady Gaga—already confirmed to be performing during the festival—would appear on Saturday night with Sting. In two words: Instant death!

The show steamrolled on, literally: The first set change from the Black Eyed Peas to Kelly Clarkson took only the two minutes that Seacrest was on stage, mostly because there was a revolving stage that allowed Clarkson's band to be at the ready. (The device helped the whole show stay amazingly on schedule.) That says a lot about the show: It was all about instant gratification. They weren't messing around with getting the next person on the stage or doling out only (well, mostly) the hits.

Clarkson launched with "Walk Away," and despite the much-less-elaborate staging (no jailbird backup dancers!), she held her own after the Black Eyed Peas. Next up was my favorite Cutter's Anonymous (of which I'm the president) song: "Because of You," which sent me into chilly spirals. That song is deadly in all the right ways, and Kelly sang it with gusto. Then, she brought her new radio offering: "Mr. Know It All," which was a thrill to hear live finally, but large parts of the crowd (not surprisingly) didn't seem to be familiar. And her final song, "My Life Would Suck Without You," capped her set perfectly.

Bruno Mars took the stage next, and served up "The Lazy Song," "Grenade," and "Just the Way You Are." And just like on the VMAs last month, Mars did his tribute to Amy Winehouse, a rousing cover of "Valerie." The whole performance came together with photos of Winehouse on the screens behind him.

Then came the most robotic, but still driving performance, of the evening: Carrie Underwood. This girl can sing, but with her coming just two sets after Clarkson, it's easy to see which of the two former Idols has more heart, and it's not this one. Still, her performances of "Cowboy Casanova," "Last Name," and crowd-fave "Before He Cheats" got everyone on their feet. Also: Carrie debuted new bangs last night. The jury is still out on them, but they were the buzz of the crowd during her set.

And then, after setting up this pop-friendly tone, the show started to veer into weird territory: Duo Karmin appeared on stage for a few minutes to do a respectable but huh?-inducing performance of Nicki Minaj's "Super Bass." And I feel bad for saying this, but I didn't really get why the next act—Jane's Addiction—was even doing at the iHeartRadio festival. I've never even heard them on the radio before! Maybe because I only listen to Ryan Seacrest in LA? But they just felt so heavy and weird in the line-up, and honestly, they brought the vibe of the show down-down-down, with their metal-leaning songs, of which I can't name one. I'm sorry, but I'm not going to even try to act like I know what was going on there or bother searching Wikipedia to try to find out the names of their songs. (Sorry!) Much of the pop-loving (and, at this point, sitting) crowd was in agreement with me on this one. Just sayin'.

But everyone got on their feet again for the next band: Coldplay. No one could resist when, after Ryan Seacrest introduced them, the symphonic, like-crack opening of "Viva la Vida" launched. People all around me teared up through the next song: "Fix You." Chris Martin couldn't have been sweatier through all of this—he is a wonder to watch live, just really earning every single note. He wins the award for Best Stage Collapse, as he fell to the ground and did a backwards somersault at the end of "Vida." And while Coldplay's old hits were exciting, there was lots of energy in the room for their latest single, "Paradise," which just hit on Sept. 12.

To be perfectly honest, Alicia Keys—who appeared next—brought the up-ness of the show down quite a bit, when she appeared. But that's mostly the side effect of her catalog and what she performed, including "Try Sleeping With a Broken Heart" and other songs that weren't as well known. It was a demure set that really only truly moved into high-flying territory when she did a medley that sampled "No One" and "Empire State of Mind," which everyone was clearly waiting for. And I'm just going to say it: Everyone—including this one right here—was sad that she didn't pull out "Fallin'." Keys is no doubt sick of performing that song, her first hit, but this pop-explosion show is exactly the kind of time where you sort of have to do that one.

The taste of "Empire State of Mind" that Alicia doled out came to full-out fruition when Jay-Z, the night's final act, appeared on stage. It was only a matter of time before you just knew that Keys would slink back on stage (photo above!)—and the crowd was dying for it. Everyone sang along, wholeheartedly, to the lyrics that, somehow, seemed to apply to Vegas in that moment: "bright lights, big city!" J, of course, also doled out a stream of his hits: "Big Pimpin'," "99 Problems," "Dirt Off Your Shoulder," "Izzo (H.O.V.A.)," and several others in what turned out to be the longest—and very possibly best—set of the night.

Readers: Were any of you there? Or listening or watching online or via your X-Box? What'd you think of the show? Tell me in the comments section below, please!

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