What do you use it for? If gaming, don't forget consider your spec, specially your video card. If HDTV, then probably you'll need 24" since it could support 1080...
Professional players will definitely keep away from LCD for a match...most of the high level players will also notice the response time lag...but if you just play for fun, i mean not care about the frag much...then probably is no problem....BTW, you could goto see the LCD in shop to feel it yourself since it can be very subjective.
Yeah I seriously don't see what some other people say is ghosting or response time lag. I didn't notice it on my first lcd (a 15" 25ms response time panel) or my current one (17" 12ms), nor do I expect to notice anything on my 2007wfp, which will be here today. I think LCDs are pretty much to the point now where they are equivalent to CRTs, so I wouldn't worry about getting one OP.