by Justin Bieber feat. Jaden Smith

(Island Def Jam)

The ongoing expansion of the Will and Jada Pinkett Smith enterprise continues apace with their number one son's leap from big-screen action hero to microphone-rocking guest-drop on the new Justin Bieber single. That's right, Jaden raps—in character, no less, as the dude he played in The Karate Kid: "Now he's bigger than me, taller than me/And he's older than me, stronger than me/And his arms are a little bit longer than me/But he ain't on a JB song with me." Corporate branding—hey-yo! In its way, this isn't that far removed from his dad's own latter-day Borscht Belt routine, but times change, and where Will got to play out his young pop iconhood with a wink, Jaden opts for a perma-pout (weirdly, it reminds me of Michael Voltaggio, who won Top Chef's sixth season) to go with his sensitive-tough-guy-of-12 mien. Compared to his little sister's ridiculous, charming-beyond-reason "Whip My Hair," his appearance here is like night and day. As for the rest of the song, Bieber is his usual Auto-Tuned blank-canvas self, an iPad frame covering an Etch A Sketch soul.

by Chromeo feat. Elly Jackson

(Atlantic)

Eighties synth-pop revivalism: You win some, you lose some. Usually, Chromeo is a pretty zero-sum game for me, but this is an exception, and it's not a surprise as to why—Elly Jackson, aka La Roux, is a guest star who earns her honorific. She's so determinedly harsh-sounding, so screechy, that she breaks through the electronic instrumentation like a rock—the loudest synth in the mix. She exudes more sheer love for the music she's making than everything else in the track put together and elevates it all.

by El DeBarge feat. Faith Evans

(Geffen)

The biggest surprise of 2010—a musical year with a lot of surprises—may have been El DeBarge's Second Chance, his first album since 1994 and, against all odds, one of his best ever. If that seems weird to you—El DeBarge?—blame his garish times and pay attention to his voice, which seems infinitely flexible and rapturous, and his melodic sense, which zigzags into places you never quite expect. The lyrics aren't much, and they aren't the point: Melody, harmony, and arrangement are—and those are as lovely as ever. It's up-to-date without seeming desperate, a rare feat for someone on his first album in 16 years—he even uses Auto-Tune artfully, particularly on his and Evans's chorus murmurs.