GTX 680 vs AMD 7970

[nicknegen]

Hi.
I'm planning on doing some upgrading to my homemade gaming PC, and I wanted some suggestions on which graphics card to use. My budget is around $400. After some looking around on the internet I've settled either a GTX 680 or an AMD 7970, but I can't decide on which one to use because they're similar in terms of performance. Here are my system specs:

Intel i7 2600k 3.4Ghz
ASUS P8Z68-V PRO-Gen3
EVGA GTX 560TI (Currently using)
16GB (4x4GB) Corsair Vengeance DDR3-1600
Cooler Master Extreme Power Plus 700W
Windows 7 HP x64

Probably won't be overclocking the GPU, but possibly a substantial CPU overclock in the near future (1-1.5Ghz more)
If I end up purchasing an NVIDIA card I won't be using SLI.
I'd like to get 80+FPS on games like Crysis 3, and Battlefield 3 with all settings maxed, and will last a few years.

Any suggestions?
I'm open to other GPU suggestions or setups as long as they're within budget.

 

[Xttony]

If you want to future proof your system to play all games at max and at 80+ fps (1080p I suppose) then you'll need a crossfire or SLI setup or you can get a GTX 690. But that is way past your budget.
Either card are great but if you are getting both the cards at the same price I'd say get the GTX 680 as it can come really handy in some games like crysis and physx based games. In most places I've looked I've seen a $80-$100 price difference between the HD7970 and the GTX680. If there is a price difference get the HD7970(as it will cost lower).
If you are willing to overclock the gpu then your card will be able to match your requirements.

 

[zzzronin]

Just check on the web for GTX 680 sluttering issues... Some peoples (like me) have big trouble with GTX 680 (and all the 600 series). It can change your decision.