The latest development in TV screens and monitors are LED televisions. First off lets just consider what LCD screens and how they work.
A matrix of coloured lenses are backlit. Each of these little lenses or windows shows red green or blue and the lenses are made up from liquid crystal that acts as a polariser for the back light. Depending on the amount of current each pixel is supplied will depend on how much of the back light shines through. For white all the light is allowed through, for black all the light is blocked and varying shades of colours are used by mixing these primary colours in their varying intensities.
Whilst these screens use less energy than the older CRT screens they will consume more energy than an equivalent LED screen. They also suffer from edge bleed and the black areas are not very black, particularly noticeably so in a dark room.
LED screen pixels are lit with an efficient array of multiple LED lights, rather than having a strong light source behind the whole panel. Each light emitting diode is individually controlled allowing for a fast response time and virtually black blacks. The screens use less energy as well so it is a big plus and they do not exhibit the same edge bleed you get with LCD screens.
You will also find that LED screens are much thinner than LCD screens as the backlights are smaller and mounted just behind the pixels at the front.
LED screens give massive contrast ratios and out perform plasma screens when it comes to power consumption and contrast ratio. (Plasma screens are still the best in terms of picture quality but with the high heat output and energy consumption they really)
LEDs also have long life spans and should last much longer than an LCD screen so is ideal in always on displays such as in shopping areas or on computer screens that run 24/7.
We are also seeing very large LED screens coming into the markets, although LCD screens are also getting bigger the bonuses offered by LED make them much better suited to be large screen televisions.