I personally like Rhapsody. I am not into the p2p sharing since I have had too many bad experiences with them. At least with Rhapsody 25, I can get 25 free streams a month as well as ad free radio. I have not had a problem with selection or quality. Overall, the best choice for me.
I voted for rhapsody, it's the easiest one to use that I've tried not to mention the whole legal thing. A buddy of mine had his ISP switched off got notice from the RIAA a couple years back and so I'd like to avoid the same.