Make it thinner lol!
YES! Keys, wallet, phone. I'm always checking to see if I have those when I leave the house. I might just duct tape them all together. I got it!
iDuctTape®
A "silent running" button. One touch and it switches off Bluetooth, Push email, wiFi, location services and 3G and hopefully preseves your power. In fact, just make a location manager that has three or four key profiles: iPhone in the car, iPhone next to my desktop mac, iPhone on the move, iPhone full monty.
I just thought of this today while using GPS and Maps earlier. In lieu of having a spoken turn-by-turn GPS navigation app, I think two things would greatly improve the usability of GPS in Maps. First, when you set driving directions from your current location to where you want to go and hit "Start" have your blue blip pin of your location STAY at the center of the screen and have the map move rather than the blue pin move and the map stay. When using it today I had to swipe along the path of my route to see where to keep going. With that functionality I'd like to have the option of hiding the text directions. Second, I think it'd be a cool option (for use with my first suggestion) to have the map rotate to put whichever way you were driving toward the top of the iPhone. It could do this by taking your initial location and your immediate next location and draw a straight line between them, then have it rotate the map so that your pin stays in the middle and the map moves down to show that you are driving forward along your route.
I think I kind of explained it poorly and if I had the ability to make a movie of what I'm thinking, I would. I think it would make Maps a LOT more useful.