Here is a very readable article that explains some of the differences between the popular but still more expensive LCD panels and the older but now very cheap CRT-based monitors. LCD prices have fallen dramatically, and CRTs are now dirt cheap--just a few years ago, a 17" CRT was $600 or more, and you can now find them for $100 if you shop around. One nice advantage of LCDs is that they are easier on the eyes, as they do not flicker like CRTs, and they don't produce ionizing radiation like CRTs.