Bach is almost exclusively my favorite classical composer. If you want some of his music, check out classiccat.net. It makes great programming music, but some of it is worth listening to when you're not distracted. (-:

I also enjoy Aphex Twin (all of the similar bands, like Boards of Canada and Autechre, not as much). I actually wrote one my of first web applications listening to "Selected Ambient Works 85-92". Ratatat is good. Finally, for some reason, I enjoy listening to the Conet Project ( http://www.archive.org/details/ird059 ) while coding.

In general though, I prefer to be in a spot where I don't have to use music to compensate for obnoxious background noise.