Yahoo! Launchcast Radio
 

This thing is the most awesome thing in existence. It's free, you get a 30-second commercial or two every few songs, but you get to customize what you listen to, to a great degree.

You choose a certain amount of bands you like, and it will play songs based on their genre, and similar bands that fans of the same bands recommend.

If you like the songs, you rate them, and the player finds more music like that. If you hate it, you tell it to never play it again.

I'm loving this shit. It's got a fairly good library too.

I listen to it alot, too.

Not sure if this is related but I have been ripping 128bit MP3 radio using winamp and streamripper for a while now. Since I started my MP3 collection has doubled, it does the ID3 tags and everything. I have too much MP3s already, I can't even find the time to give each song I rip a listen. I have not used Kazaa or any other file sharing program since (at least for MP3s).