My car is going be covered with paintings and line drawings, as if I used it as a giant travel journal on my imaginary trip west on Route 66. So when I was trying to decide on a color, I gravitated to the warm cream color of the pages in my Moleskine sketchbooks. It's a little more interesting than white, but still easy to paint other colors over. If you like to peek in the sketchbooks of different artists (I do!) there are lots to look through at their flickr group Moleskinerie.