Older than the F6? That's really old. If I were in that situation, I'd get a used SB-28(DX) or SB-80DX in addition to an SB-900.
Regarding color filter automation and a 200 mm zoom reflector, you don't really need that. Seriously. Velcro is your friend: buy gel filters, add velcro to your flash and to your gels and presto. If you want a zoom reflector that works up to 200 mm, make a snoot. It's easy.
The SB-900 is really a good flash and from the looks of it, the UI is better, too. Personally, I can't justify upgrading from my SB-600, though