The 460 should be enough to max ALMOST everything with the exception of AA, but IMO I can't tell a difference between 4X AA and 8X AA. Also, what mobo do you have, maybe you could get the 460 now, then SLI it later for some crazy performance. There are reviews of the 460 all over the net, I'd check one out if I was you.
I have a Asus P7P55D PRO.
It can SLI 8x/8x. Does have too much difference between 16x/16x?
Thanks everyone for the answers!
Really don't mind about playing with everything in higher quality possible (AA; AF; Ultra Mega High Settings etc
) I will stick with the 768MB for now...Probably, I'm going to sell it in the future and/or buy another one (1GB this time) and do SLI.