it's for a new build, going with a i5-2500k CPU, and one of the new Z77's. The 680's are still sold out on newegg, but i'm not sure if it's really with the extra couple hundred bucks to get the 680 or a 7950 or the 7850.
680 is really an outstanding card in my opinion and worth $500 and here is why:
1. Best FPS to $ ratio right now
2. Fater than two 570s in SLI- which cost about 275 right now new.
3. Mine idles in machine at 26 degrees Celsius and gets to 50 after gaming on it for 5-6 hours.
4. Uses little power
5. 2d and 3d surround off of one card
6. Adaptive Vsync- I really like this piece of software
7. FXAA- I notice a huge difference in games like SWTOR, enabling this in the control panel, graphics always look much better.
8. When you need more power these will be much cheaper and you can SLI.
9. Not out yet but 4 gigs of VRAM is awesome, 1 gig for every monitor if you run four, 1.33 for each if you run three! Tons of power!!!
7870 is a spectacular card. I'd probably wait on the 680 but if you can't wait, the 7870 is sick. A 580 can be found for really big discounts right now though so at least price/performance wise it's still a good option. But personally it would be between the 7870 or the 680, and I'd take the 680.
I do like the GTX 680. It's exceeded my expectations, but the 7970 is also good, especially if you use GPGPU apps.
They both overclock to reach similar performance. I chose the GTX 680 because I have a 3D Vision monitor, and really like 3D. FXAA is also a nice feature, and eventually they will be releasing TXAA which will take it up a notch.
7870 can be better than 580 but not in all benchmarks.
the price difference is U$ 50 normally. (1,5gb vs 2gb) personally i would go with the 580 if was that the choice, but i recommend waiting for a 680.