I got my Dell 20" Ultrasharp Widescreen for under $400 a month or so ago. You'll have to watch for coupons, btu it can be done, and it is the best monitor I've ever owned (I believe the LCD on it is of the same manufacture as the ones Apple uses, though I may be wrong on that). In any case, the resolution on it is solid enough to work for a graphic designer (me), so it will be more than enough for everyday use.
-Colin