I don't know how flat LCD monitors compare in terms of the specs available, but I would personally only buy a very expensive one.
From my experience (I am using one right this moment, at another person's house) colors alone are reproduced very well, and the monitors are very bright...but there are other problems. An LCD monitor has an ideal angle to look at it with... and so moving your head 8+ inches off that ideal point, causes that typical LCD effect where the image gets darker and becomes less visible (similarly to the effect of the LCD on the back of digital cameras). This is especially deceiving with sharp shadows and black colors.
The other problem with LCD monitors are the pixel specs. Once again, the more expensive the monitor the better those specs will be.
But then again, for the cost of one of those expensive flat LCD monitors, I would rather buy two relatively expensive 19" monitors for a dual monitor setup.
/2tall/