I once saw a concept car that touted a solar roof, not for charging the battery (Although it did that, albeit only slightly) but for running the AC off free electricity. It seemed like a really great idea for a hot summer day.

Really, if the solar panels do enough to let me run the radio and maybe charge a phone... that's pretty good. Where I live, I need to have a car, and if that car can double as an emergency source of power, all the better.

That said, the price tag is way too high, but it would be great of some of the ideas this car represents found their way into more modest vehicles.