I am a big fan of higher resolutions, and believe that should be a big factor in your decision. The world is so much better at a higher resolution. If you go with a 22" monitor, you're probably looking at a 1680 x 1050 resolution. It is great for games, but getting to 1200 on the height is much better for browsing websites, typing documents, or doing anything that would usually require some scrolling. I actually prefer a 20" non-widescreen monitor at 1600 x 1200 than the 22" wide screens.
.....but....
If you want the best of it all, and have the video card to support it, a 24" widescreen monitor at 1920 x 1200 will make your single-monitor multi-tasking excel! Games on a bigger screen are much better, and some games will actually show you more stuff. If your videocard can't handle it, then a 24" monitor will drive you nuts in games.
The difference between 2ms and 5ms is almost indistinguishable to the human eye. If you can see a difference, then you have one amazing machine, or you've got a software problem.
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