This late entry for hip-hop anthem of the summer (slated for T.I.'s new album) comes down to a four-way braggadocio battle – and with a beat this hooky, everybody wins. Still, Kanye West scores the best lines, including the succinct instant classics "My swagger is Mick Jagger" and 'Tm Christopher Columbus, y'all just the Pilgrims." And Jay-Z loses a couple of points for sticking in an overobvious nod to his single "Jockin' Jay-Z." Meanwhile, Lil Wayne's surreal, Auto-Tune verse initially sounds lazy but ends up mesmerizing with its lunacy: "I require what I desire," he drawls, "running this shit like I got four thighs." The song is built around a sample of M.I.A.'s "Paper Planes," marking the latest step in her belated assault on the mainstream, after the Pineapple Express trailer push for the same track. Good for her – except that it's hard not to be slightly bummed by the prospect of one of the decade's most innovative artists being reduced to a hook girl.

“I'm Yours”

Jason Mraz re-emerged after his disappointing second album with this lead single, a Jack Johnson-esque ditty about giving yourself fully to someone else. The success of the reggae-tinged song (it earned two Grammy nods and a spot on the Billboard singles chart for well over a year) was something the folk-pop singer never predicted when he wrote it in 15 minutes at home. "I played a happy-hippie chord progression that would probably work without 50 different Bob Marley songs," he told Rolling Stone. "I thought, 'It's too novelty. This is a nursery rhyme,'" concluding that "you can never guess what's gonna be a hit."