I have XM Satellite Radio at home and in the car. I really like it. One of my favorite XM channels is 75, Hear Music, "the sound of Starbucks." They play a nice variety of new music and a mix of other stuff that is upbeat and energetic. (...like Starbucks coffee? I wouldn't know. I don't even drink coffee!)
I have also found that some of the music artists I like have Myspace sites where you can hear their music. Here is one I like. They are called Guster. The song I like is Satellite.