I'd keep the frame black tbh. It won't be as much of a pain to clean, it retains the original look (might be useful when you sell it) and it'll be far easier to touch up if need be.
If you want something different, do the plastics a different colour or if you want to stay with black, a really nice, deep metallic black or something. At least if you change your mind later all you have to do is take the panels off rather than dismantle the whole bike!
Like others have said though, if you don't plan to keep it long term it might be more economical to keep it as is and save the money to spend on a real tidy bike next time. Wish I'd told myself that before.