I use a HP lp2475w. An amazing monitor that shares the same panel as some of the really high end $1200 NEC's. Though it is a bit more pricey, it is a H-IPS panel. Which means you'll have the broader view angle, sharper colors (especially your levels of black), and decent response time. Response time isn't quite as fast as some of the cheap TN panel monitors, but its not much slower. 4ms compared to 6ms. Both in grey to grey.
http://www.amazon.com/LP2475W-24in-L...5962949&sr=8-1