I haven't boughten* any music in a while, and I have a $15 Itune's gift card to burn.
I listen to just about anything except heavy, heavy metal, most country, or really obscure music; for work out music, it just has to have a good, continuous beat. This isn't for on the bike or running, but music to wake me up and motivate me after I crawl from my bed to the floor in the morning to work out for about 30-60 minutes.
Also, this doesn't have to be "good" music. It has to be good work out music. I've listened to some horrible music over the years working out that I otherwise wouldn't have, but it kept me going...
*most of my music is from friends, not downloaded, although I'm not sure there's a difference legally.