It's interesting that people are saying they get less eye strain from LCD, because that's the exact opposite of my experience. I get much less eye strain from CRT.
However, I think it's down to refresh rate. Since LCDs use an always-on backlight, you can run them down at (default) 60Hz with no flickering. However, CRTs will flicker at this refresh rate, and you need to set the rate much higher - 85Hz is about optimal. My experience is that very few people actually do this, and I have in the past been called "a magician" for "curing" people's persistent headaches where all I've done is re-set the refresh rate. Some people can't see the flickering consciously, but it's still straining their eyes (there is a wealth of evidence that you see much more than you consciously apprehend).
In my office, I have done round all the machines with CRTs that are in my field of vision, and asked their users to re-set their refresh rates (and done it for them if they have been unable), because I don't want their screen giving me a headache. I get some funny looks at the time, and then they come to me and thank me for doing it a few days later.
As far as the quality of CRTs goes, they pretty much have to be full flat screens based on the Sony Trinitron tube (you can detect this by faint grey conductor lines at 1/3 and 2/3 screen height). The Mitsubishi DiamondTron ShadowMask displays were never as good.
All you guys with your Dell monitors are almost certainly using Trinitron tubes.