Ray, I've found that it seems to vary from person to person.
It also depends on the make & model of the CRT or flat panel monitor, as well as the type of screen work you do.
Entering into cells in large spreadsheets, I found large CRT better for prolonged usage which surprised me. Flat panel is fine, but somehow the CRT has the edge for me.
Conversely, word processing is far better on flat panel IMHO.
Gaming is much better on CRT; better for the dark scenes and fast moving action that doesn't smear/blur.
So you should go and try out some flat panel and CRT displays to find out your own personal preferences, noting down the model and make as they seem to vary in quality quite a bit.
Hope that helps.