The Swedish synth-pop duo Icona Pop sound like the female half of Abba kicking Fernando downstairs in a drunken rage – or maybe Ace of Base if the sign they saw was flashing blue lights. Caroline Hjelt and Aino Jawo grabbed attention last summer with their Eurotrash club hit "I Love It," bragging about how miserable they were going to make that ex. But U.S. success hasn't mellowed these ladies or tamed their hard-partying, man-eating sensibility. On aggro-disco stomps like "Top Rated," Icona Pop could convince anyone they're the wrong ladies to mess with – they chant over these electro beats as if they're still wearing last weekend's makeup while hurtling to their next Saturday night.

Listen to 'Iconic'

“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."