Actually... it's not. LED backlit LCD was created so LCD could do something as close to what plasma was doing. Same with refresh rates... they're just not applicable on a plasma but again, something LCD had to do to keep up with plasma. I have yet to see an LED LCD come close to what plasma can offer... even at twice the price plasmas are unbeatable. Even the brand new "local dimming" LED's can't get near the black levels of plasma.
As bcoop said above, it's all dependent on what room it's going in. If you have direct light on the screen and have no way to control it, you're stuck with LCD (not a bad thing you'll just have to spend more to match what plasma can do if you like great looking screens). If you don't care, just a cheap 60hz LCD will do.
How far back are you sitting from the TV... that's the only real question when deciding on 720p vs. 1080p as the closer you are, the least likely you can tell.
Other things to consider:
-Contrast ratios are meaningless. It's an inmeasurable number if they're using dynamic contrast. They should be using ANSI contrast but 948:1 doesn't sell TV's (true measured contrast)... 1,000,000:1 dynamic contrast does.
-Don't look for the TV with the "best picture" to your eye. They're all set to "Torch mode" on the shelfs to have the maximum brightness. Bright does not equal a great TV... it will give you a massive headache though. Get your TV home when you buy it and put it on cinema mode... you're half way to a calibrated TV now.
-Do look at owner's threads on AVS and another great place is plug the model number into amazon and look for reviews and star ratings on TVs with more than 20-30 respondants.
-There is no such thing as "Plasma burn-in" There is "image retention" but it should go away after a few minutes. This was a problem with early plasmas 6-8 years ago and just never was able to shake the stink off of this since so many early adopters got burned with this (no pun intended).
-Plasma's draw their power dynamically... bright scenes will get up to 400-500 watts. Dark scenes can draw as low as 18watts. Power draw is peaks and valleys on a plasma. LCD TV's draw a consistant amount of power (380watts for instance for a 50"). I'm saying this because another bad wrap about plasmas was they are a power hog. It's because folks looked at the peak number and took it as constant like LCD. Side by side they draw almost identical power over the span of a movie or TV show.
*I do not own a plasma. All of our locations that we watch TV in have too much glare but I would KILL to have a Panasonic Plasma. The only room I have that would work I have a 120" projector setup in.
32" Sharp Aquios (Guest Room)
50" Samsung DLP (living room)
46" LCD (bedroom)
Mitsubishi 3LCD HC6500 Projector (Media room)