6950 1GB vs 6950 2GB?

I guess in games/programs that utilise the 2GB buffer (or if you are playing at resolutions of 2500x1600x32 with 8x AA etc) you would see a difference (lack of dips in fps). But those are very few yet. If the price is right, go for the 2GB.
 
If you game on a single reasonable monitor (1920x1080/1920x1200) the 1gb model should be just fine. That or a 560 Ti. But if you have plans for a multi monitor setup I would recommend the 2gb version.
 
so far in modern games the 2gb is only faster at rediculously high resolutions, but who knows, a new game may come out with extra high res textures and fill up all that memory.... if i were buying a higher end card like that, i would get the 2gb. 6 months down the track you may regret only getting the 1gb version.