As I understand it, life expectancy (and energy usage also) lines up as follows:
Florescent = first generation flat screen TV/PC monitor (lots better than old ?tube? TVs).
LCD = second generation flat screen (much better than florescent).
LED = third generation flat screen (best by far!).
?3D? LED = fourth generation flat screen (very pricy & long term market acceptance somewhat debatable. Life expectancy, quality, etc, expected to be same as standard LED).
I?m not sure where ?Plasma? fits in but I believe it to be generally between Florescent and LCD. Plasma TVs came out about the same time as florescent but they have been improved & upgraded so the current models are more like second or third generation in quality, life expectancy and features. From what I hear, plasma energy costs are fairly high but the viewing quality is superb. Note: The plasma market share thus number of manufacturers is dwindling (ie: beta-max?) so some good deals can be had.
I do not know the exact numbers as far as life/energy but LEDs are a lot more energy efficient (by at least an order of magnitude) over LCDs, LCDs by another order of magnitude over Florescent so over time each may pay for the difference in price. Note: 100,000 hour life expectancy (LCD/LED) equates to 34+ years at 8 hrs a day ? ie: both LCDs & LEDs will outlive your interest in what?s on TV in all likelihood. Generally, each generation of TV also includes more features (ie: audio/video/PC connections) compared to the previous generation also
Almost all of the florescent TVs on the market now are cheap clones assembled by no-name far-east manufactures using left over parts (or left over older models being dumped by brand name manufactures) ? simply put: I would avoid florescent TVs/monitors like the plague. LCDs are starting to do the same ? older/cheaper models & knock-offs.
?3D LED? is too expensive and there are too few 3D shows (DVDs, etc) to justify buying for the next year or so in my opinion.
Thus: Currently, I would look for LED as my first choice. But: Many brand name manufactures are trying to get rid of LCDs so they are priced very competitively right now (and should be even more so for the Christmas shopping period) ... again I'd stick to newer, brand name, LCDs though.