It looks like that resolutions are doomed to grow. An average gamer plays on the 19 inch 1280x1024 display, some lucky ones have 1650x1080 resolutions on their big wide sceens and only a few rich ones can afford a 30 inch display and pay up to $2000 for 2650x1600 resolution.

The new Nvidia card will let you play at  3840 × 2400 but only at 30 Hz which is two times 1900x1200 resolution. I am not aware of any display or device that can bennefit from this Dual link DVI-I output but obviously there will be a purpouse for such a resolution. It is a cool pixel number but un cool refresh rate as you need at least 60 Hz to make your eyes feel good.

 
In worst case scenario it is a nice tick box feature, that you can state on the box and impress anyone.