the 6950 2gb hands down is the better choice, two 6770 isnt any faster and even in crossfire you'd still only have 1gb of Vram ... and at the resolution you plan on playing you can really use the 2gb the 6950 offers
Yes, the x4 will be the bottleneck for the second graphic card. The 6770 is around $120 each before MIR so I'll assume your budget is more of the $240. At that price, I would either go for the 6950 you were considering or a 560 ti. If you want, the 6870 performs really well at high settings.
Other than the x4 bottleneck. Some reasons not to go crossfire is the temperature and heat produce. Driver support are not that great for crossfire compare to single too.
Alright.Yah that's what I thought but i had forgotten.
I always reccomend the 2G cards because I know that I would someday like to run eyefinity.Of course that's not the same intention with everyone else but I think it's always good to have it just in case because you never know.