I got one of these back in June:
LG IPS226V-PN 21.5"W, IPS PANEL, 1920x1080, 16:9, 5MS, D-SUB, DVI-D, HDMI
http://www.lg.com/au/it-products/mon...IPS226V-PN.jsp
I'm very happy with it, a great price for an IPS LCD and these guys make the panels for Dell. Great dot pitch as well.
I used to have a CRT (1280x1024) prior to getting this one and the jump up in resolution to this flat screen did cost me a few FPS in COD, so watch out the higher you go the worse your FPS will be. I ran almost everything on maximum settings on the CRT but had to lower some settings when using the LCD.
Also for size, I'm of the opinion that in games size doesn't matter. You focus on the game and don't notice if it's 27 inch or 21 inch. I think size for monitors is for more desktop real estate when you are editing multiple documents etc. For a better dot pitch (for spotting the enemy at a distance) you'd want a high resolution on a smaller surface, so if two monitors have the same resolution but one is larger, then take the smaller one.