I should've been more clear - sure, 680 can run at 1080p, but very few games will get less than 60 FPS on Ultra - basically, it's a waste of graphics power. I'd personally sacrifice a few FPS here and there on the select games that can't be run at 60+ FPS at 1080p... and go with a higher-resolution monitor.
Don't you guys understand? 1920x1080 at 27" is only 81 PPI. 2560x1440 at 27" is 109 PPI. That's 35% higher pixel density on the higher-res screen. You can have 32x AA on a low-res low-density screen, but it's not going to look as nice as a modest amount of AA on a higher-res screen (example- technically on a Retina display, you'd need 0x AA because you couldn't see the pixels). It follows, you don't need as high of AA with higher-density displays, and (I'll get to it), a GTX 680 is actually good enough for 2560x1440 BF3/high. http://members.ping.de/~sven/dpi.html
http://www.hardocp.com/article/2012/05/14/geforce_680_670_vs_radeon_7970_7950_gaming_perf/3
In summary, you're approaching the problem the wrong way if you think gaming at 1080p with a $500 card is doing it right.. Framerates and benchmarks only get you so far. Higher image quality, due to a higher-quality display, get you the rest of the way.

















