What device to get?

The only way you can do this is to get an unsubsidized Nexus One, and that isn't cheap. Right now you want to have your cake and eat it too, but it's not in the cards.

 

i know there is a couple of media players, sort of like an itouch that will run android. but as others said your asking for too much. honestly your better off just using one device and pay the slight extra for the phone service, because your going to need to pay for 3g anyway, unless you plan on just using wifi