A very interesting music subscription service has opened up recently. Pandora.com has indexed the musical "styles" of a crapload of music, some popular, some not-so-popular. The really cool thing about this particular service is that you can create multiple "channels" by seeding it with the name of a band or a song. It'll then analyze that song and deliver in your channel songs with similar musical qualities.
It's really quite good at what it does: Pick your favourite song and create a channel based on that...I've been listening to my Eric's Trip and Chixdiggit channel for most of the morning, and I've heard maybe two songs I didn't like.
Give it a try. Unless you're on dial-up :P