Heh, if I had a 8800GTS (any type) right now, I'd totally sell it if off and get a 8800GT or 3800HD later.
People on EBAY are dumb, last time I checked (bout a week ago) they are still paying top dollar for the obsolete techs. Net a good 230ish on that card, then buy a 8800GT for about 250. Just got yourself a GTX basically for must less $.
With the release of the 3800's, the 8800GT should drop a bit in price, provided the 3800 is priced right and nearly as powerful.