You know what is so sad, up until yesterday I had 5 straight Nvidia cards starting from 3dfx, 6800xt, 8600gt, 8800gt, and the 9800gtx+........ Even by looking at my logo I loved Nvidia, its support, drivers, physx, its affiliated games, and evne the brand.... But I just got a 5850.
It is out of this world and I couldnt wait for FERMI or any of Nvidias GTX300 series..... While playing the original Crysis I did notice that the physics is a little different. Somehow the barrels and trees did feel a bit different in sway and bounch. I do think I will miss PhysX. It will take some time to getting used to but it is such a minor thing. Only a game like Crysis can make you realize the difference. Otherwise the framerate was so much smoother than my 9800GTX+ at Very high settings.
As for the Fermi series or Nvidia, it will take some time to come out as we have not even seen prototypes out on the web. SO if you are looking for a good card to buy, like me, DO NOT GET THE GTX285 and buy the 5850. Then when Nvidia comes out with the 300 series and hopefully it will be cheaper(highly unlikely) then wait for prices to go down and THEN buy one.
I got my 5850 here for $276! What a steal!