When buying a LCD flat panel monitor what should I look for before buying one? Is a TFT display good?

Plus I need one that works well for computer games. Preferably a 17" LCD monitor is good. How good should the refresh rate be?

How much should I be willing to spend? Should I buy it online?

Thanks

This should help you out

http://www.hardware.info/en-UK/articles/am5naWpxZA/TFT_monitors_buyers_guide/