670, 680, or 7970 ghz edition?

In the near future (around the end of the month), I'm going to be building a new system pretty strictly for gaming. I've pretty much settled on all the other components, other than the most important: the GPU. I've also considered waiting for the release of the 8000 series, but I'm currently gaming on my laptop which is capable but not ideal, and with some estimates as far out as June or July, I figure it'd be better just to pull the trigger.

I'm going to be running at 2560x1440 (with a side 1080p for sys monitoring if that makes any difference), which I hear the AMD card is slightly more capable at.

The 670 and 680 seem capable cards, and are said to have lower frame delay for a smoother picture.

In terms of raw performance, however, the 7970 ghz trumps the other two by a wide margin.

In addition, some of the games I play (BF3, the Witcher 2, Skyrim, etc.) seem to like Nvidia chips a little better.

So, basically, I need a little help making this decision. All of the cards I'm looking at are within the same price range, so price shouldn't really be taken in as a factor here. Which is the better card for my needs?

Thanks!
Moosie 

7970

That's what I've decided on. I've heard they're stupidly power hungry, though. (The Ghz edition.)

If I crossfired did a 2-way crossfire down the road, what wattage would you reccommend if I'm also overclocking and whatnot? Would the 850-Watt I'm considering be enough?

850W would be enoughfor crossfire

although in general i would not reccomend corssfire unless you are using multiple monitors

Be wary of AMD drivers. Had both I prefer Nvidia.