I agree with Anita. If I'm trying to write or do anything that requires creative thinking, the quieter the better.
On the other hand, if I'm doing something like housework (which I try to do twice a year whether it needs it or not), I crank up the stereo and boogey oogey oogey.
If I'm doing something mundane like organizing my files, I like to listen to audio recordings. I think I've downloaded about a zillion "free" lessons, interviews, etc., on Internet Marketing... and I just can't find the time to listen to them all.