My opinion, not worth a lot but going to give it anyway!
Screens I have owned....
Panasonic PW6 (liked it but only 480)
NEC 42XM3 (hated it, inage retention, poor blacks)
Panasonic PHD6 (Loved it, phosphor trails and some posterisation but only slight)
Pioneer 435 (Hmmm, hated it, looked nice off and on a bright scene, black levels awful!)
Panasonic 50PHD8 (loved it in every respect other than it was a alittle big for poorer SD in my room)
Pioneer 436 (as the 435, plus the motion was not great, slight judder)
Panasonic 42PHD8, swapped the 50" for the 42" because the 50" was a little big. Very happy with it and had it two and a half years now.
I tried a Pioneer 428XD, in fact two but just couldn't get on with the twittering pixels. Got rid and hung the Panny back on the wall.
Then tried a 508XD as was told they are better, but the same.
Panny back on the wall.
Then bought someones 508XD off them as the pixel problem was meant to be better on later sets. It might have been a slight improvement but I think if it annoys you it will annoy you no matter what.
So the PHD8 came out of the bedroom and went back on the wall.
I also had a PX37 in the conservatory, no where near the level of the PHD8, blacks not as good, noisier in the dark areas, phospor trails and some posterisation which really annoys me.
Plus with it being a conservatory it was not bright enough, so I bought a cheap Samsung 37" R87 screen.
I have to say it has been great.
I needed a new screen that was all in one, something for the bedroom but also something I could put in the front room when I move my sound system up to the loft, so started looking at what is about, and for the first time I didn't write off LCD.
LCD is a weird one when doing demos, the one area that sells them in a store for 90% of the population is also the area that lets them down to those that are a bit anal when it comes to image quality and what they want, and that is luminance!!
These thinsg can go bright!! I mean really bright. The backlight on the Samsung 7 and 8 series, which are the ones I narrowed it down to go from 0 to 10, at 2 it has more output than most plasmas, in stores the default is 6!

So yeah it makes it stand out, and makes any plasma seem dull, but at the same time it makes everything on screen look like a Stickle-Brick world. The noise round everything is just too much.
So just knock the back light down to 2??
Well you do that on the standard settings and it looks like a washed out mess, like you have cranked the gamma, everything looks cloudy and there is no punch to the image.
I bought an LE756 Panasonic. I have been fiddling with the options and settings for 3 days, not constantly, but tweaking them with different programmes. If it got 90% of the quality of the PHD8 I deceided I would be happy with it, it is only a TV for news, and the odd show; films etc. will be in the cinema room.
I will now say the following.
95% of the time this is the best flat screen display I have seen. Period.
It has already replaced the Panasonic PHD8 as the main set, the PHD8 has gone to the bedroom (although for sale as my better half thinks 42" is far too big in there, and I have to agree).
I have the back light on 3 which if you did in store you would just walk away from it.
I have adjusted the RGB offsets and gains, turned all the processing off, half the sharpness, set to WARM, etc. etc. etc.
With the PS3 it is breathaking, this walks over every single plasma out there period.
But I am not that big a gamer any more so just a bonus for me.
HD - Now with HD material this is sharper than anything I have seen before, the motion is smoother, the colours are just sublime, they are so natural looking it has blown me away. But more than that is the overall feel and level of detail, watching Jaws 2 last night you could tell when they swapped to a different camera, even my wife commented on it, and she really doesn't care about image quality at all.
SD - Decent SD feeds on this are better than the plasma, not by much but they are better, which was a bit of a surprise I have to admit.
Poor SD feeds are also just as good, now this is even more of a surprise, after living with the R87 and its terrible black levels I thought all poor SD on an LCD would always look really bad, but because this thing can do black it just isn't the case.
Sports beat the plasmas too, sharpness, colour and the real shocker...motion!

Now all plasmas suffer from Phosphor delay, some you can see and some you can not, but they all suffer and this comes across as a slight blur on those where you can't see it like the Pioneers and Panasonic commercial screens from series 8 upwards.
Watching the football without this is a revelation. Now I do watch a lot of sport, and for me this is probably the main reason I am swappinng the plasma over, I just love it. Even the Spanish footy with its crap SD feed looks great on here, it always used to annoy me on the Panny, well I used to get annoyed with the broadcatsers. But on this it is great.
The only negative with the whole set is around the 2ire level, set the backlight higher than 3 and you get a slight clouding in that region, you can overcome this by cranking the black adjust to LOW or MEDIUM if you need to set the back light higher and it will crush detail in the 2 to 3 ire range, but if you need the backlight that high it would be more than crushed with any other display anyway.
There is also an contrast that adjusts when moving from a bright to dark scene, but this can be turned off I found out this morning.So not really a problem.
So, in a very long wided way of saying it, what I am trying to say is this, we all tend to be very ignorant when it comes to stuff other than we have bought ourselves, just look back at my posts over the years.
I have however said that I will use whatever I feel is giving me the best image at the time, I am only a plasma fanboy when they are the best, and likewise any other technology, I don't care who makes it, I don't care what it is, and although I do care what it looks like hanging on the wall when off it still has to perfrom perfectly for me when on, if it doesn't it gets the boot.
So right now I think the gap between LCD and Plasma really has closed, those slagging off LCD really should see one properly set up, it might just shock you!