It's the same internet, just in the car. Use your imagination.
The GPS real time traffic is definitely possible depending on the program you use for GPS, and I'm sure there is a way to log your GPS data and put it on the net for some kind of vehicle tracking. The Voip phone/camera would work same way it would at home.
Having a regular wireless card in the car is helpful sometimes too especially for data transfer. You can pull into your driveway, connect to your home wireless network, and then pull files downloaded off of your desktop to your car.
Uhm...you could stream pandora (Music genome project) in the car. www.pandora.com it's a pretty neat little website. (if you really wanted you could capture the requests and parse them to find a link to the actual music file and download the mp3s to the car as you're streaming them...i'm sure this is frowned upon though)
I'm not very creative