The color of any given car does not impact one's ability to maintain it's cleanliness.
So, you're planning on spending close to $10 k on paint, but don't plan on maintaining it (depending on the color choice)?
Or, you're willing to accept less than perfect body work if it's NOT going to be painted black?
Care to guess what color I'd pick?
(It's your car, don't let your gf push you around!)