If you haven't used it before, Pandora is basically a web site that lets you choose a song or an artist that you like from an insanely large selection, and it will try to play music that matches your taste. It has worked really well for me so far! Try it out:

http://www.pandora.com

"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram