Crysis 3 is the exception not the rule. If all games were as demanding at that Crysis 3, then a lot of gamers will be screaming at AMD and nVidia to release much more powerful graphics card ASAP. If you can accept medium quality graphics for this game, then 1600x900 or 1920x1080 are definitely doable.
I suppose the ultimate question is what do you consider the minimum frame rate for a game to be playable? Also different games actually have graphic modes. In some game "high" is not maximum graphic quality. Some games have "very high" as well. I think one game had "uber" above "very high". So the question is how high is "high"? Absolute "maximum" graphic quality? Or something in between medium and "maximum"?
1600x900 is the safe answer at this moment because Hitman: Absolution is playable based on the above benchmark. But you should expect mid to high 30FPS with the Athlon X4 750k, not 41.3FPS that the i7-4770k @ 4.2GHz is getting. While Hitman: Absolution (and Metro Last Light) is not as crippling as Crysis 3, it is still considered more demanding than your average game. Taking that into consideration make 1920x1080 a more viable option. You should be able to play most games with max graphics with at least 50FPS. Demanding games means you will need to drop down to medium graphics for better performance.