Just dealt with thiis last week. Wife has been squirreling away for one for a while now. Got FIOS TV service and they dropped an HD set top box so now there was no stopping the wife.
Plasma/LCD. I have been told they do not last as long as Projection. Projection bulbs only last a few years and are expensive $200-300 to replace. I normally do not get an extended warranty on elecrtonics purchases but for projections they generally include 1-3 bulb replacements which you WILL eventually need so you break even on the out of pocket and get some piece of mind.
720P, 1080I, 1080P.
P=progressive, I=interlaced
720P ='s 730 scan lines
1080I ='s 540 scan lines (replicated) Interlaced can also flicker.
1080P ='s 1080 scan lines
A 720P will yield slightly better resolution than 1080I .
1080P has 1.5 x's the resolution as 720P.
Most of the projection boxes that you see in the $1200 range are most likely 720P.
Right now more HD is broadcast in 720 than 1080, bandwidth issue.
Within the next couple of years most HD will be broadcast in 1080.
Right now a lot of sports are broadcast in 1080.
Cables. Here's where they hose you. DO NOT let them talk you into a $200 HDMI cable.
HDMI carries video and audio and is a digital signal. Fancy gold plated ends are NOT going to improve the signal. it's digital, passes 0's and 1's. You can get HDMI cables on line for $20 that will yield the same picture. The cables are a huge profit center for retail.
Also depending on the mix of peripherals HDMI may not be the best. Get HDMI and Component cables and see which one works best for your configuration.
HDMI passes copy protection which could mess with any "recording" that you may want to do.
If you don't have a TIVO or DVR then you can build a nice Linux based MYTH TV box.
http://www.mythtv.org/ Don't let the fact that it's opensource turn you off. It is very highly regarded. Some people are starting to sell them turnkey for $1000. You can build one in a day for less than half of that.
View them at the store with the contrast cranked way up.
We were looking at either Mitsubishi or Samsung. Went with the Samsung 61". Color and clarity were hands down better than the Mitsu. Wife found nothing but positive reviews on the Samsung.
Just start hitting boards and read, read, read. Expensive purchase. You don't sound like the kind of guy that wants to live with a bad choice.
The worst part is that you may get a bit frightened when you see your local newscasters in HD. Shows WAY more detail than you really want to see.
And as far as flaws in the picture you will see tons on non HD broadcast. Signals are compressed and you will see JPG compression artifacts. Worst on the kids cartoons since the have so much large flat color areas. The more detailed the image the less you see it.
The other annoyance is the different aspect ratios of broadcasts, it'll switch between 16:9 and 4:3 constanly, usually the commercials are 4:3.