S!
Only reason I would jump to 680GTX from 7970HD is that it would increase the MINIMUM FPS in games drastically, not only 5fps or so. A few FPS is not enough, it has to be a lot. I run VSync + 60Hz monitor at 1920x1080 so my target is 60FPS with no dipping or stuttering which I pretty much achieve now with my 7970HD. Add to this the upcoming patch and we will see how performance settles.
Will negotiate with local computer store to get one 680GTX and pit it against my 7970HD in my rig(see signature). Then I could see how it performs in games I play..no synthetic benches or boring FPS games
Nevertheless seems to be a good card!