Apple iPhone 3G
Apple's very uptight about what to allow. I really don't know why. I guess just protecting themselves. Maybe the battery life on a turn by turn GPS would die quickly. BUT if you're in the car, you'd probably have a car charger.
It's one of those things that Apple wants to be praised and revered when they do release it. That's how they roll. Hopefully 3.0 will allow this in July this year.