if they only sell limited numbers... i think they could sell the 480 for 650$ easily...
especially if its on average 30% faster than a 5870... in that case they might even be able to sell it for 700$ in limited numbers...

they have held the performance crown for a long time, and have a lot of fans that are happy with their cards and dont have a problem with spending that much on a new highend card.
especially since many people think this will be a G80 scenario i wouldnt be surprised if many nvidia fans see it as a long term investment...

i have never been interested in nvidias highend cards, they were always too expensive and had too bad of a perf to price ratio for my taste... same for atis highend cards actually...
so i really hope they hurry up with GF104 already... ati could def need some competition in that field