Anybody heard of
http://www.pandora.com?
My housemate told me about it a few days ago, and its one of the coolest things out there for music. The site asks you to pick either an artist or a song, and then afterwards it will choose a song/artist depending on the one that you chose. You then have the option to give the song a "thumbs up" or a "thumbs down" and it will give another recommendation based on that. The site also allows you to create "radio stations" based on the artist/song that you originally choose, so the next time you go to the site your preferences are already there.
Obviously, since it's streaming audio, it works best with a faster internet connection. But if you haven't been there, I recommend you at least check it out. For me personally, it has already introduced me to a bunch of artists/songs, that I would never really know about unless someone pointed it out to me. With this site and allofmp3.com, I think I'm set for music for a very long time.