You have to check out www.pandora.com. It's an internet radio station, with a twist. You type in the name of a band you like and they play songs that are similiar. It's pretty incredible. After listening for about an hour I'm left with the impression that they are digging through all the cd's on the floor of my car and playing songs at random. Seriously. I don't own that much music, but they have played only one song off an album I don't own.
Check it out!