Although she’s still not known to the public at large, British singer Imogen Heap seems to be on the verge of a breakthrough. Her album “Speak for Yourself” got the notice of critics, Zach Braff (who featured “Hide & Seek” on the soundtrack to his movie “The Last Kiss”), and the National Academy of Recording Arts & Sciences, who nominated Heap for Best New Artist. Imogen garnered even more publicity when she showed up at the ceremony wearing what looked like a Chia Pet on her head. Publicity stunts aside, this young lady, like kindred spirit Feist, deserves your attention. Check out her new album, “Ellipse”, in stores today.

Also arriving in stores this week:

Arctic Monkeys “Humbug”-These young Brits have garnered a steady helping of critical acclaim for their first two albums, and they have been hugely successful in their homeland. “Humbug”, their third full-length effort, was produced by Josh Homme of Queens of the Stone Age.

Colbie Caillat “Breakthrough”-The sunny singer/songwriter sold 2 million copies of her debut album “Coco”, which featured the hit single “Bubbly”. Fresh off a hit duet with Jason Mraz (“Lucky”), the sunny chanteuse is back with her sophomore effort, which has already spawned a hit with “Fallin’ for You”. If Caillat’s name sounds familiar to you, it’s because her dad, Ken, engineered the great Fleetwood Mac albums of the Seventies. Some favors were apparently called in with this album, which boasts super-producers Rick Nowels and John Shanks, plus songwriter/”Idol” judge Kara DioGuardi and a guest spot from John Mayer.

Matisyahu “Light”-Five years ago, if you’d have told anyone that a reggae-singing Hasidic Jew would be a successful musician, you’d have probably gotten laughed out of wherever you were. However, “King Without a Crown” turned Matisyahu into a star, his last album went Gold, and he’s looking to successfully sidestep the sophomore jinx with his new album, “Light”. This album was produced by David Kahne, who’s claim to fame was Sublime’s successful self-titled effort.

Michael Jackson “The Definitive Collection”-Expect a slew of MJ releases between now and the end of the year. This compilation is nothing special-just the umpteenth set that recaps his Motown career. Featuring both Jackson 5 and solo hits, this album also includes the “stripped” mix of “I’ll Be There”-which appears on yet another useless compilation called “The Stripped Mixes”. Color me uninterested in any Jackson compilations until they start putting out the unreleased stuff.

A full list of this week’s releases can be found here.