Via my friend Scott, I've discovered Audioscrobbler, which is a really cool music application for your computer. You download their plug-in and it keeps track of what music you're listening to on your computer. Then, it takes that information and collates it and matches you with other people that listen to similar music, as well as making recommendations for other music you might like.
Check out my page here.
And to no one's shock or surprise, Scott's pretty high up on my Musical Neighbors page.