This is from the australian photography site as written by Nicholas N
Forget refresh rates guys, it's all about the quality of the panel.
There are 3 main types....
TN - Twisted Nematic - These are the most common types as they are cheap, feature fast refresh rates which is great for gaming but produce low quality images.
VA - Vertical Alignment - Best widely available monitor for photo editing that wont damage your bank account.
IPS- In Plane Switching - The Rolls Royce of screens, the best and most expensive option if you are serious about editing.
If I were you I would ensure you are buying a VA panel at least, forget the resolution, the screen needs to be able to give you the smoothest and best image possible.
Dell make some good VA panels, they call them Ultra Sharp and you will notice on the Dell website they clearly state which of their panels are TN and which are VA. Other manufacturers hide behind refresh rates as the be all and end all. The Dell 24" Ultra Sharp is around $769 which is well worth the money for the image quality. The panel features a 6ms refresh rate which will be fine.
Seriously consider what you buy now to avoid dissapointment.
Read this site, it will bring you right up to speed on the above panels I have mentioned.
LCD Technologies
Regards
Nick
PS I did go on the Dell site and found a good VA 20"Ultra Sharp for approx $AU470
cheers