Say this for the 17 popstars who teamed with the greatest living singer of American popular standards: They're brave. Luckily, Bennett rescues most of his partners. (Josh Groban and Andrea Bocelli drip so much goop on their ballads, even Bennett can't mop it up.) Aretha Franklin and Bennett blow the roof off "How Do You Keep the Music Playing." Amy Winehouse reminds us what we've lost in a huskily sensuous "Body and Soul." And Lady Gaga whoops through "The Lady Is a Tramp" with such gusto, you can hear Bennett grinning.

Listen to "Body and Soul":

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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."