This week's hot tracks from Katy Perry, Coldplay, and Nas

By Leah Greenblatt
July 04, 2008 at 04:00 AM EDT

Katy Perry
”Hot n Cold”
The ”I Kissed a Girl” singer forsakes flirty bi-curiosity for this throbbing ’80s throwback that damns a lover who’s…well, you know. Could it be about her on-and-off boyfriend, Gym Class Heroes frontman Travis McCoy? Either way, it’s damn fun.

Frontman Chris Martin, more assured and lyrical than ever on the band’s fourth album, channels solo John Lennon, cooing mournfully through a delicate, guileless piano ballad that turns midway into a propulsive rocker.

Nas feat. Keri Hilson
The irascible MC spares no one on this synth-laden screed from his upcoming as-yet-untitled release. But R&B songbird Hilson’s pretty backing vocals soften confrontational lines like ”Try telling Bob Dylan, Bruce, or Billy Joel/They can’t sing what’s in their soul.”