Depends, what resolution are you playing at? Higher resolutions will appreciate the 1GB of VRAM but until you exceed 1680x1050 you dont need 1GB of ram and a 4770 or 4850(both perform very similarly) will perform better.
thank guys....I will be most likely getting the 4770, though i think I'm be trying to find one 4850 about $100 since I've read a few reviews saying that they drop the price......