Gray, white, or Pickering?
Paint with whatever color goes best with the decor in your house....Make sure you use a quality primer and wash with TSP first.
I guess it really depends on the rest of the style of your home such as country, rustic, etc. I suggest getting a piece of oak wainscoting from the store (or take off some of yours in an inconspicuous place (if there is one) and try a sample of each. This way, you can see how it looks side by side and determine which one you like best. Good luck! Post some before and after pictures. We'd love to see what you did!
You could get a small sample paint from Home Depot for around $3 and paint a couple areas and see what you like best. If you don't want to paint the wainscoting then paint a piece of cardboard and hold it up.
Usually white or black
White is always classic and will always be in style. It goes with so many decor styles.