How do the two technologies work?

Plasma HDTV
Phosphor, a chemical compound, is the heart of a Plasma HDTV. The light you see on a plasma screen is caused by these phosphors. Each pixel in a Plasma HDTV is made up of three types of phosphors, red, blue, and green. When beams of electrons strike with these phosphors, they emit light. The amount of light depends upon the intensity of the electron beams.

LCD HDTV
Where phosphors play a major role in the technology of Plasma HDTVs, in LCD HDTVs, it is crystals. Crystals, in the form of liquid, is sandwiched between transparent panels. There is a bright florescent light behind these panels. The sandwiched crystals are
instructed to either let the light pass or not. Color filters are also used, which determine the color.

Does size matter?
Since both Plasma and LCD TVs are large screen televisions, size does not matter that much. However, if you consider viewing area by size, Plasma TVs have always been a good choice. Again, you can find more varieties of Plasma TVs in comparison to LCD TVs. On the other hand, if by size you mean the size of your bank account, it matters indeed. For the same size, Plasma TVs are normally less expensive.

Viewing Angle
The viewing angle is the feature that determines how far off to the side you can sit from the TV and still see the picture clearly. It is very important to consider the viewing angle because not all of your family members can sit literally in front of the TV. When it comes to viewing angle, Plasma TV has a definite edge over LCDs. Some LCD-manufacturers claim that the 170-degree field of vision offered by them allows accurate viewing. That is not true at all. You may be able to see what is happening at that angle, but it is not the same as sitting more directly head on.

Issues with Plasma and LCD HDTVs
There are certain issues with both Plasma and LCD HDTVs. The following details will help you understand them.

Problems with the Dead Pixels
There are certain problems with pixels in both the televisions. Sometimes pixel is always ON. For example, it lit up when the
screen is black. Sometimes the pixel is always OFF. For example, it looks black when it should have color.

You must buy your HDTV from reputed manufacturers, because in that case there are lesser possibilities of such problems. Again, if you face any such problem, reputed manufacturers take care of it.