More aboutsafe temps nvidia geforce 8800gt experience
id say getting over 85 is too hot. but what you see in furmark will never be what you see in game. 90 in furmark is probably ok. use msy afterburner to log temps and play the games you normally play and go by those temps.
Furmark has long been referred to as a heat virus by both ATi and Nvidia, with decent coolers on the temps probably won't get much above 65c when gaming.