Half the games there are only playable at 2560 with no AA; some of them aren't even playable at 2560 at all. Sorry if you don't see it that way, but I'm not spending $700+ on a new monitor to play at lowered settings.
The HD 7970 wins at 2560, but that's merely academic for the reasons outlined above. If you're going with CF/SLI, then clearly the HD 7970 would be a better choice. BTW, the 3GB of VRAM was included and huge memory bus was designed exactly for that reason: more than enough VRAM and bandwidth for CF at 2560x1440 and higher.
Personally, I'm not planning to spend more than $350 on a single monitor (like most people), so the HD 7950 doesn't look like that good of a proposition against the GTX 670 unless there's a price spread of at least $50 between both. Overclocked to 975-1000MHz the HD 7950 will definitely catch a stock GTX 670, but at higher power consumption (remember the GTX 670 can still overclock too, and even if scaling isn't as good it'd still gain performance). I care about performance/watt, and I'm pretty sure at 900-925MHz with a small undervolt the HD 7950 would have higher PP/W than a GTX 670, but it'd have a bit lower performance, and a decent amount less performance if the 670 is running at 1100MHz.