you do not need wifi to talk and surf on the web with the motorola droid. i can be surfing the internet, answer a call on the phone or bluetooth, and use the gps at the same time. it helps when your sitting in the passenger seat and have a car charger.
gps is stored when you first download it. and for surfing on the web while on the phone, all you have to do during conversation is hit the "home" button. slide the apps arrow up, and hit browser. EVEN WHILE YOUR WIFI SETTING IS "OFF"
i travel all over michigan, ohio, indiana and never have any problems in the car multitasking with the phone. also you can multitask tons, like listen to music while surfing the web.