Vanquish pointed out some of the good with these things. I won't go into that - he was right so why tell you why you need one of these things.
The key to using an LCD for gaming is unfortunitly money at this point. Couple things to consider when buying these monitors.
1 - Size: you really do get increased viewing size when you buy one. I replaced a 19inch CRT with a 17inch LCD and actually gained some space. To that end - more size is not better. You can buy a 19inch LCD for what might be the same price as a good 17. The difference is that the 19 just has bigger dots and the same native resolution.
2 - Speed - The refresh rate of the monitor will tell you if you can play games. Believe it or not, even racing games with huge refesh requirements can be played on a good monitor. I have a monitor that allows me to do this, but I spent a lot! I have a Hercules Profitview DVI. I have no ghosting at all, but I paid for it. If you goal is gaming and you don't want delay / ghosting either stick with the LCD or be prepared at least at this point to pay for it.
3 - Prices of high speed LCDs may come down. If you can wait, it will help.
4 - GET DVI!!!!!!!!!!!! This is not a small difference. Make sure your card is capable of DVI output and the monitor has native DVI input. Do not comprimise on this issue.
5 - Manufacturers lie about refresh rates. I can talk about this all day. Esentially there are two ways to measure. Be careful. If you ned help - I would be happy to - but read this article first:
www.tomshardware.com
Good luck.