Try posting in the video forum, there's also an LCD selection guide there. As for good response + large size, that doesn't exist yet.
You won't get world record response times with a panel larger than 19". All of the fastest ones are currently 19". Of course, if you arn't a hard core gamer and would like to have a larger monitor, there's many suggestion in the gaming (slower response, higher contrast) heading in the LCD selection guide.