Romeo Santos — who, in Aventura, fronted the world's most popular Latin band — is a ladykiller with an unearthly falsetto that recalls Aaron Neville's. His debut solo single blends Dominican bachata with R&B — plus coos and come-ons in Spanish and English — with predictably suave results.

Listen to "You":

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“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."