The 2560x1600 resolution can only be had on a 30" monitor , the newer 27" monitors coming out now have 2560x1440 and it's almost the same but just a bit lower.http://www.newegg.com/Product/Product.aspx?Item=N82E16824260038http://www.newegg.com/Product/Product.aspx?Item=N82E16824001523http://www.newegg.com/Product/Product.aspx?Item=N82E16824260111
These are some of the high end monitors that are out now with that 2560x1440 resolution and as you can see in looking at the spec's they all have 5 -7ms response time. I had a 27" 1920x1080 Lg that had a 2ms respnse time and went to a 30" HP 2560x1600 and 7ms response time and did not notice any difference in gaming. Depending on your gaming skill set you may or may not see any difference.http://www.newegg.com/Product/Product.aspx?Item=N82E16824185011http://www.newegg.com/Product/Product.aspx?Item=N82E16824236294
These new 27" monitors also have some new features like;
Wide Quad High Definition
Delivering four times the pixel resolution of HD, the 27-inch ASUS PB278Q is a 2560 by 1440 Wide Quad High Definition (WQHD) monitor that brings incredible definition to your games, videos, and everything else you do.
The PLS panel provides an ultra-wide 178-degree viewing angle and a superior matrice design compared to other panels for enhanced definition and detail.