The problem you face is that for a gaming monitor you want to be looking at response times of 16 or less. Most 19" have 25 or more. However you should remeber that the viewable size of a 17" is comparible with that of a 19" CRT.
I am sure there are good - ie. fast response time [16>], lots of colours, good screen etc. - 19" TFTs out there but you will have to pay a premium.