I remember from the early days of DTP that reflective surfaces on many large scale monitors weren't totally unwelcome...
mostly to catch a quick peek of good looking girls passing by behind the workplace
But seriously TFTs are a true relief. Not only the heavy magnetic field and static load, but also the emission of high to ultrasound frequencies of CRT tubes produce a lot of subconsciuos stress.
Another strange effect is the typical color generation of mixing 3 dots to one color.
Compared to a grey scale monitor this alone is way more painful, even if the dots virtually melt into one, at least this was my observation.
And finally the 'active' viewing angle has a significant influence. A 'lanscape' of 3 17" or 19" screen with important details spread over all the area is a totally unnatural thing - and after some hours your head feels accordingly
cheers, Tom