This is tough, but thankfully Wikipedia helped me remember all the releases. And also all the music I still got to check out!
January: Contra by Vampire Weekend, Of the Blue Colour of the Sky by OK Go
February: Odd Blood by Yeasayer
March: Tourist History by Two Door Cinema Club, American Ghetto by Portugal. The Man, Broken Bells by Broken Bells, Congratulations by MGMT
April: Forgiveness Rock Record by Broken Social Scene, Treats by Sleigh Bells, Brothers by The Black Keys
June: Barbara by We Are Scientists
August: The Suburbs by Arcade Fire
September: Lonely Avenue by Ben Folds and Nick Hornsby, Invented by Jimmy Eat World
October: Belle & Sebastian Write About Love by Belle & Sebastian
Unknown: Vision Revision by Architecture in Helsinki, Fleet Foxes by Fleet Foxes
Still gotta check out the new Massive Attack, deadmau5, Kayne West, and Jamiroquai.
Tourist History is probably my favorite at the moment.
Edit: Oh, and Matt & Kim - Sidewalks, I'm from Barcelona - 27 Songs from Barcelona.