Do you plan on upgrading your monitor?
If so, then my build would prove to be useful. With my build at your resolution, you shouldn't have any problem at playing on ultra settings at a comfortable fps.
Here's a youtube video benchmarking the hd 6870 @1360x768.
In games like Crysis, he's frequently dipping in the 30 fps range. You can watch the rest of the vid for yourself. I don't have the time at the moment.
Hope this helps.