After a couple of days of thought and using both services, I've decided that I like Rhapsody much more than iTunes.

The $10/month fee provides a lot of flexibility to try music, and having burned a CD from both services, I think they're the same (to my untrained ear) from a quality perspective.

Although I don't have an iPod, the portability issue is the only chink in Rhapsody's armor that I see right now...