I run pretty much all my games at 2560x1600, except one, because that particular game only goes up to 2048x1536. That same game also does not support wide screen. While running the 'wrong' resolution on an LCD doesn't look optimal, my screen has a very good dot pitch so it actually looks pretty good still. My video card (an 8800GTX) does screen and aspect scaling, so at least I get to still play the game fullscreen, or I can set it to keep the resolution aspect, in which case any other resolution looks exactly the same quality as the native on my screen, except the image is smaller.
Also, I build my computers to be fast enough that I anticipate being able to run any game at 2560x1600 for the next two years or more, at reasonably high graphic settings. Hence...why I overclock the CPU
. I can always add a second video card for SLI when I need to, my board supports 8GB RAM, and it supports quad-core CPU's. Besides...I get all my parts for free...sorta!
I've found it interesting over the years, as I've sold thousands of screens to as many people. I run into a very small minority of people that HATE lcd screens. They claim, (and I believe them) that even at the proper resolution etc etc, that its very blurry, they can't read it properly, gives them headaches, eyestrain, etc. For myself, I left CRT's a long time ago and have stayed with LCD ever since. I find that CRT's will give me a headache after using one for a few hours, even at refresh rates over 100Hz. I can stare at an LCD for 12 hours or more straight and...other than looking (and feeling) like a zombie, feel fine.
In the end it comes down to available choice, individual preference, and, of course, the almighty dollar!