"Just for the record, of a quick count of recent games/AAA titles, Borderlands 2, Max Payne 3, Dragon Age II, Hard Reset, BF3 multiplayer, CoD:MW3, Total War: Shogun 2 (since the latest patch), and WoW: Mists of Pandaria -8 titles- favour the GTX 680 over the HD 7970GE."
GTX680 lost its advantage in BF3 for a while now. Your information is outdated. They are roughly equal in multiplayer and many websites show HD7970 Ghz faster in single-player.
Here is multiplayer:
"The HD 7970, GTX 680 and GTX 670 were all able to perform at 2560X1600 with FXAA High enabled. From a raw performance perspective, the HD 7970 was faster than the two NVIDIA cards, but not to the extent that it was noticeable within game play."
http://www.hardocp.com/article/2012/11/12/fall_2012_gpu_driver_comparison_roundup/4
COD:MW3? A console port that can be maxed out on a GTX560Ti, no one cares. If you want to bring up COD, at least bring up Black Ops 2 as it's probably the latest title COD fans are playing on the PC. It's pretty obvious that the frames are so ridiculously high with flagship cards in COD games, it makes no difference to playability. No point in discussing irrelevant performance difference in COD games.
http://www.hardocp.com/article/2012/11/26/call_duty_black_ops_ii_performance_iq_review/4
Same for WOW that you mentioned (5 fps difference above 100 fps) and less than 2 fps at 1600P. Again, irrelevant as this game's performance will vary by more than that based on the CPU rather than HD7970 Ghz vs. GTX680's choice.
http://www.techpowerup.com/reviews/HIS/HD_7950_X2_Boost/23.html
Borderlands 2 can be maxed out on a GTX660Ti. So the only way NV has an advantage there is through PhysX. Hard Reset - again not GPU demanding to make a playability difference, but I'll give you that one. That means from your list there are only 5 games and in some of them the difference won't be felt. Of course there are more than 5 games where NV is winning among 1000 games in the world. My statement is more to say that in the most GPU demanding and latest titles, you can count on 1 hand significant wins by NV. Assassin's Creed 3 will run faster on NV cards.
Ironically, where the extra power really helps more often happens to be AMD cards are leading in the majority of cases. That's not in games like Hard Reset where you get 80+ fps already or WOW where you are above 100 fps:
- Crysis games
- Medal of Honor
- Arma games
- Alan wake games
- Hitman
- Sleeping Dogs
- Dirt Showdown
- Anno 2070
- Metro 2033
- Witcher 2 enhanced edition
- Skyrim with ENB mods
When GTX680 behind in the most GPU demanding titles, it's often losing by 20-30%. In the games you listed when GTX680 is winning, it's doing so by 10-15%.
NV's cards above $300 are currently overpriced. A $360-370 1Ghz HD7970 delivers GTX680 level of performance, HD7970 Ghz after-market cards like Asus Matrix are faster than any 680 and GTX670 is getting destroyed in price/performance by after-market HD7950 cards. $280 HD7950 925-950mhz cards are 10% slower than GTX680 for way less $$:
http://www.techpowerup.com/reviews/HIS/HD_7950_X2_Boost/28.html
Contrary to you already painting me an AMD fanboy, I really don't have an allegiance to either brand. I just find it amusing how NV buyers always defend their purchases but I rarely see the same from people who buy AMD cards from time to time. Typical NV buyers will buy NV generation after generation no matter what. These type of gamers are easy to spot since instead of criticizing NV from dropping the ball this generation and not giving us the real GTX680, they defend the brand and won't acknowledge that NV went from having a 20% lead with GTX280/480/580 against HD4870/5870/6970 to losing the single-GPU performance crown, while charging MORE for their slower product. The real NV never showed up this round.