Anything except rap, really, because I don't consider rap to be music.
Favorite bands/artists currently are Snow Patrol (and I liked them pre-Grey's Anatomy!), Lifehouse, Simple Plan, Boys Like Girls, Creed, Corinne Bailey Rae, Colbie Caillat, Amy Winehouse (Rehab is an awesome song), Alicia Keys, Michelle Branch, Carrie Underwood, etc...