Hmm... I can't listen to music while I work--it's too distracting.
When I do listen, though, my radio dial is all but glued to the classical stations. I enjoy Mussorgsky, Bizet, Stravinksky, and Verdi.
I do occasionally get a yen for some folk music, so I have Silly Wizard, Clannad, Eden Burning, the Boys of the Loch, the Appalachian Christmas Quartet, and some others handy in my (very dusty) CD rack.