Well, the 7800 GT is awesome card. More bang for the buck compare to the GTX. It can play fear really well, but disable softshadows and dynamic light cause its' the games frame rate killer. 1 Gb is decent, but if you play BF2 then you might wanna consider 2 Gb. But right now the best one to get is the 7800 GT for system. Go for it.
But Im pretty sure you can pawn 2 Gb for less like a value ram. Not really the best, but I use 2 Gb value ram in one of my system and overclocked it. It was awesome, play FEAR and BF2 with no stutter whatsoever.