Im using a BenQ Gw2750HM, its a 27" AVMA monitor, can game with a 4ms GTG response time and has a 5000:1 Contrast ration with a 178 degree viewing angle, so colour reproduction is good, and the best part is its only about 250$ if you find a deal and 300$ regular
I'd suggest the Nixeus Vue 27, which is the monitor I have now, but they keep raising the price because of its popularity. It used to be $400. I got it for $500, and now it's $600. It's a 27" IPS panel with a resolution of 2560x1440 and a 6ms response time. It's a really nice monitor, but you'll have to adjust the color when you first get it because the factory settings are pretty terrible.