I got a Viewsonic VX2250 a year ago and it has been great. Sitting next to my friend's IPS iMac display the Viewsonic really holds its own, though the latter isn't actually IPS. The viewing angles aren't as good, but they are pretty good. Its still getting very high ratings and costs only about $150.
If I were to spend much more, I would be more concerned with getting a feature like 16:10 aspect ratio (16:9 annoys me) or a pivot.