IMac :: ATI Radeon Hard Drive 4850 GPU?

Loving the new iMac revisions and have placed my order for the Core i7 configuration with 8 Gigs of RAM, the only thing that slightly concerns me is Apple putting the ATI 4850 GPU in this machine as this card has been around for well over a year. Having a young family my iMac really has to last me (current Mac is my old but faithful 800Mhz G4 Angle Poise 17" screen iMac) so don't want to get caught out with an "old" GPU that within a 2-3 years won't be able to cope with current day demands placed on it. My usage is photo manipulation, a bit of FCP and I want to be able to play some 3D games etc. but I'm by no means some games enthusiast who requires the highest frame rate, highest settings. Figure I have two option:

A. Bite the bullet now - this iMac has almost everything I want - been waiting for Quad Core desktop chip and LED screen but icing on the cake would have been better GPU and Blu-ray option.

B. Wait yet another update (figure March / April 2010) in the hope that Apple put in a more current GPU and possibly Blu-ray option. HOWEVER I figure that this is probably a fools game as who knows regarding Blu-ray and obviously a more current GPU will be fitted but probably won't be the most extreme one as Apple tend not to figure that this is a priority on the iMac.

My inclination is that this update will probably be absolutely fantastic and my GPU worries are probably unfounded as I'll never want to push it to gaming extremes but interested what others may think.