Wait for the GTX 680. You won't kick yourself like I did with my buying a AMD 6970 because I could not wait for the GTX 580.
Me, I am just such a NVidia fan after I got my GTX 580. Stable, great drivers, no BS stuff loaded with the driver (here's looking at YOU, LOTR), and a profitable company. Also, folks are starting to push the stock GTX 680 on air into unreachable territories for ANY form of 7970 to reach.