unless you are on lynix or XP Pro don't put in 3Gb becuase it's not as fast as having only 2Gb.
also you won't need a faster cpu for a while. i think your best bet is to wait for the Dx10 cards to come out and get one of those since teh 7800 is pretty good already. unless you're really picky w/ FPS and having all graphics maxed out and high settings just aren't enough for you then stay w/ it and upgrade later.
if you feel like upgrading soon (for the sake of upgrading mostly) then look into liquid cooling or more Hard drive space.
that's my 2 cents.
