First Smart Phone

Still don't know which of the Eris or Droid I want
One of the main reasons I wanted a smart phone was to be able to listen to internet radio streams in my car but that seems a waste now that I've learn what these things can do. I'm intrigued by the google navigation (Droid only). I have a lot of iTunes music that I'll have to deal with to transfer over.

I've been thinking about this for 2 months now. I like the look and feel of the Eris but I'd hate it if I felt like I'm stuck with something under powered right off the bat. My "New Every 2" came due last week and my contract runs out in March but I don't have to make a decision any time soon.

Any suggestions?