If I were to limit "driving" music to songs that explicitly mention driving a vehicle, I'd have to say that my favorites are:
-Radar Love = Golden Earring
-Asleep at the Wheel = The Bloodhound Gang
-Hit and Run Holiday = The Thrill Kill Kult
-Jesus Built My Hotrod = Ministry
-40 Miles to Vegas = Southern Culture on the Skids

...and some more that escape me at the moment. I really should sit down with the collection and burn a real driving CD.