Panny 50" Viera Full 1080p PLASMA here. Fantastic TV and I would never go for anything else since. Owned Sony, samsung, LG etc and they are all good, but not quite as.
I don't like the blacks on LCDs and the fact that even with the massive improvement in viewing angles you still only get the best picture if sat in the right place.
With the video processing on the Panny sets, SD material also looks good. Trouble is when you buy a cheaper HD telly is that you usually sacrifice a good quality video processor. (not usually an issue if all you do is feed it a HDMI/DVI signal though)
Don't forget, it doesn't matter how good the panel is, it's only as good as the picture you sent to it