As someone else said, it'd probably be better to wait for a second gen. The way I see it, by then, they'll have had a longer time looking at the DirectX10 API and be able to better utilize it's functionality.
That's what I'll be up against at the tail end of my 90 step-up period. Should I just jump on board the first gen 8800s to get $250 off and possibly kick myself when better cards come along w/ DX10 games and Vista to back them up, or should I wait for the 8900 to go down to current 7900 prices and pay the same amount for better hardware, but have to wait a year to do it?
Heck, I'd probably be happy with a 8500/8600 if it comes out in time.