Is there any difference in reliability or lifespan between CRT and LCD monitors?
Not that I'm aware of. The method of failure is obviously different, but LCDs have three distinct advantages:
1) Smaller footprint takes up less space
2) Less Electricity (I honestly don't know how much that adds up to savings per month)
3) Easier on the eyes
(3) is my big selling point. Being a codemonkey, I stare at a monitor all day, and I can attest to the easy of staring at an LCD vs CRT. The CRT monitors really do a number of my eyes, while the LCD monitors are much easier.
That, and the prices are coming down so quickly that there's little reason to NOT get an LCD. If you needed this in November, on Black Friday, Best Buy had a 22" LCD for $150 (which a few of my friends picked up).