Since this is a tech discussion, I read that plasma screens do better in low light rooms, i.e. dark rooms...lots of windows, or external light sources reflect off the screen making it difficult to see the picuture...not so with LCD HD.
This is one complete lay-person, non-techie, non-early adopter opinion, but I'd simply say few "normal"
people can see the difference between plasma and LCD. I have one 42" of each; the plasma is older, 720p, and the LCD is newer, 1080p. Both look remarkable, both are a giant leap up from the older technology. I'm very happy with both, and both types of these are relatively inexpensive now (relative to the value, imho, not relative to older TVs, however).
As for bright rooms, my LCD is in our family room, lots of light, still looks terrific; my plasma is in our game room, much darker, also looks great. Can't go wrong with most HDTVs these days, imh(and uneducated)o.
And if you want to watch the recent Steelers Super Bowl victory or Pens Cup victory, just come on over, I still have them on the DVR, can't bring myself to delete them!
Hope that helps.
I can't even imagine wanting to watch anything in 3d, but maybe that's just me. I've never seen anything I thought was remotely good, particularly since you have to wear the glasses. My dad has a very old (circa 1950s) stereo camera that takes better 3d slides than anything I've seen before or since (you have to wear special polarized glasses, not the red and blue cheapo ones), but to me, it's just an annoying novelty (but please don't tell him I said that...).