How different do you want it to be from what you have?
I like the burgundy on it so you could respray it that way if you want, but if you want something a little different but not too drastic check out Garnet Red Pearl (3K3).
Garnet Red Pearl was only a color on 92's and I've had a hard time finding pics for it, but it looks really good. In fact this car is the only one I've seen it on:
http://www.cardomain.com/ride/2283034 He used to be on here but sold his 92.
I think something like Imperial Jade Green (6Q7) or a similar green would look really good. It was a color offered on Mk4's, and I think it's one of the rarest colors on it.
http://www.cardomain.com/ride/435207
Of course, you can never go wrong with black. It's definitely one of my favorite colors on a MK3.