I moved from a 19" 4:3 CRT to a 22" Widescreen, Very Happy.
Ive just recently built a new PC with a e8400 and a 4870 so am now considering moving to a 24"... However Im also considering 2x 22" and tbh I'd consider the amount of space I get from 2x22" to be vastly superior to playing games at a slightly higher res on a slightly larger screen
IMHO if your sitting at your desk then a 22" would be adequate, Ive also used this for watchin movies on whilst in bed and I've not had an issue with it.