For overall monitor clarity, CRT monitors are the way to go. They offer better refresh rates, and higher resolution support.
However, if your graphics card has a DVI (digital output - white rectangular socket) socket, then you'll find that things will look a lot sharper on a TFT with DVI support (as opposed to VGA - blue trapeziod socket).
For gaming with TFT monitors, response time is key (the time it takes for a pixel to go from off to on and back off again). 12ms and below is preferred, as you might start to see motion blur on anything above this.
A high contrast ratio of 500:1 and above coupled with a brightness level of 250cd/m2 plus will ensure that all the colours look the way they should.
http://www.aria.co.uk sell monitors at very competitive prices.