It used to be most rock, but heavy, metal, and screamo.
But I just don't bother anymore. It's either way to depressing or about hot chicks or something stupid.
When I was in high school, I listened to a lot of rap/pop because of my friends. It has some fun beats and stuff. I grew out it, though.
Right now, I don't have any favorite genres. I just listen to musical soundtracks or game soundtracks. >.> I'm nerdy like that. I don't even listen to my favorite bands anymore. O_oa