Your options are fairly limitless given what you have already. It really depends a lot on your style. I can picture a rich purple or a pretty gray, or even decoenthusiaste's suggestion of something to match what is inside the glass cabinets at the top. I would suggest heading to your local paint store and grabbing swatches that appeal to you and then looking at them in the space to see what works. And feel free to post pictures with the swatches here for comment.