I just rediscovered Pandora Radio. It's a free online radio service where the listener "defines" the music. I love how you feed the station with favorite artists or songs and then it plays music that matches those styles. You can read more about it here: Music Genome Project
And if you feel adventurous, you can try listening to my main station Cindy's Jukebox (also listed in my "tunes" links at the right). Be forewarned, it's a pretty eclectic mix.