Dave Winer muses today on the possibility of cars with WiFi. I'm not sure I'm wanting to wait for the auto makers to figure this one out. His post expresses a thought I've had for a while. Our cars need to be able to connect to our houses and to other Wifi networks we might see along the road. Now with some tools like USB cable modems the possibility of being connected in more places is even possible (though doing much music syncing on EDGE would be slow).
Several folks have already done modifications to put Mac minis in cars. We already know that these little computers can drive the car on their own so why not expect a complete data system. At the end of the day I'm thinking I'd rather have an after-market system that easily plugs into the car over a system that comes with the car. The Prius has a great GPS but since it doesn't interface with the systems I use it is less useful than it could be. While an interface would make it more useful, it would still be yet another system and type of system to figure out how to integrate.