If you had AT&T I would suggest the Mil-Spec phone line that we have. That way you could drop it and not worry about it.
Seriously though for Sprint, I would suggest the Moment. It is running the Android 2.1 software, slide out full keyboard, very good display, 3.2 Megapixel camera. Full featured and all of the Android (Droid as commercials commonly call it) apps that are available. Last time I checked (about a month ago) there were over 27,000 apps available of which about 1/2 are free.