I'd like to see this in two applications:
1: Built into some cellphone models and integrated with 911. I wouldn't mind having a gps chip in my phone if it would help me out during an emergency. I just moved to a new town and don't really know my way around yet, so if I witnessed an accident, I may not know where I was enough to help an operator. Same goes for driving on the interstate, I try and check mile markers, but I don't always do it.
2: Built into pocketpc's with some sort of updateable yellowpages you can sync with Activesync. The ultimate would be a pda/phone combination so you could look up the nearest chinese place and call them for takeout from the same device
The current pda/phone combos don't impress me though, so I don't expect to see one out there that I'd actually use