even if you do have a 1920x1440 or higher display, it's not really a necessary upgrade. Being able to run some games @ 1600, and every game @ 1280 4xaa/8xaf, I don't feel the need to plunk down $600 for a bit higher resolution. if it actually offered more features, perhaps.. but not for the ability to run a bit higher res.
might be worth it for those who were looking to upgrade their old cards (r3xx, nv3x and older), but from an x800/850 or 6800gt/u, $600 is not a very good price/performance upgrade.
those that have money to burn, or have the need to own the fastest card avail may find a reason to upgrade, but heck.. i buy this stuff just to play with the tech, and i find no desire to upgrade...
until something like ut3 comes out, or the price drops about $200, I doubt I'll have the urge...