Automatic settings via the localization service (GPS)
iPhone should have an menu to to automatically switch On/Off wifi, 3G, Bluetooth, etc., depending where you are located via the localization service.
Many users, like myself, use the phone in various situations/places. Due to battery saving, I'm always switching 3G, Wi-Fi, Bluetooth, etc. On and Off.
Ex:
At home - I just need Wi-fi connected, BT and 3G Off.
At work - Same thing
On my auto - Bluetooth On, 3G on and Wi-fi Off.
Etc..