Man Pandora is so much better than Sirius for music listening.
I've had it on at work for a good week and haven't been disapointed.
http://www.pandora.com
Dana and Chris already use it, but to those who don't know about it, you select as song or artist you like and it will just play an endless list of songs and artists similar. You always have the choice of killing it from your list if you don't like it.