I listen to everything. Actually, classicals are extremely rare, and most of the time, it's pop-alternative rock. Once in a while, I'll pop in a Country mix CD, but nobody will have to know about that(I listen to it, only when I by myself in the car).
Currently - Bootlegged Jack Johnson live CD(I love this thing).
Week ago - Mix CD of Cold War Kids, Brandi Carlile, Paolo Nutini, White Zombie, Keane, etc.
Before that - Frank Sinatra's "Very Good Years"
I used to like techno as driving music in my earlier 20's.
Edit: Obviously, I mistakenly posted my real driving music here. In game, I also turn off the music.