This if you'd like it on the cheap at 23":http://pcpartpicker.com/part/asus-monitor-vs239hp
This if you'd like it at 24" and with a slightly different aspect ratio:http://pcpartpicker.com/part/asus-monitor-vs24ahp
Finally this if you'd like to go big on 27": http://pcpartpicker.com/part/lg-monitor-27ea33v
- They're all within your budget
- They're all Full HD (1920 x 1080p)
- They've all got a response time at 5ms and not 1ms higher, which is good
- They've all got IPS, which makes colors much prettier
So it's down to preference.