Favorites are Mozart, Brahms, Bach, Chopin, and Beethoven but like dfranke 'omnivorous classical' is a pretty good description. But I will pretty much listen to anything.

Some of my favorite performers are John Eliot Gardiner, Andre Previn, the Kronos Quartet, Cecelia Bartoli, Murray Perahia, Mitsuko Uchida, Emmanuel Ax, Alison Hagley, Bryn Terfel, and Yo Yo Ma.

And I also often prefer quiet when hacking, and only listen to music to drown out distractions.