Consider what the primary uses of your machine will be (games vs spreadsheets vs layouts, ect). Hit the local 'puter stores and compare each model; and do it at several stores. I looked at a Viewsonice PF790 at Best Buy and it was the pits, looked at the same model in CompUsa and it was decent.
Also think of how exacting you are in viewing; some models give you extensive control over color, divergence, rotation, ect..
I ended up buying the KDS AV 19" (and love it), but the Mag 810 was a close runner-up and both are in your price range.
good luck