2 560 ti or 2 6950 2gb or 2 6950 1gb

Just upgraded to a i5 2500k and a Gigabyte z68 ud3h motherboard

Got the I5 at 4.0 ghz for now, may or may not push it harder in the future considering it does have plenty more to give

But for now Im looking for graphics power to match.

So should I get two 560ti in Sli or two 6950?

I was looking at two of these: http://www.newegg.com/Product/Product.aspx?Item=N82E168... $460 but $410 after rebates

Or two of these: http://www.newegg.com/Product/Product.aspx?Item=N82E168... $500 but $440 after rebates

What do you guys think? Would 1GB be fine for video memory or should I bite the bullet and spend more on 6950 2GB? Any other good sli(preferably) or crossfire options out there at around this price point?

Edit: forgot to mention my psu is a corsair 750hx psu

Monitor Resolution: 1920 x 1080

Purchase Date: within next 3 weeks, after move in to campus

overclocking: probably not, but if i can i may tinker with it at some point

Budget Range : $400-$500 the cheaper the better, but I want some kick butt performance for Battlefield 3

Sli is preferred but I'm willing to do either