Liquid Crystal Displays have become very popular in the HDTV market because of their thin size and bright picture. LCDs compete in the same market with plasma HDTVs and often offer better viewing in rooms that have a lot of ambient light. Plasma HDTVs are better suited for darker rooms, as the blacks tend to be deeper, thereby creating a better contrast ratio. LCD's brightness helps it perform beamingly well in mainstream, light-filled rooms.
LCD HDTVs suffer from "motion blur," quite literally the blurring of fast motion on screen. To combat this, manufacturers up the refresh rate (how often an image is displayed on screen) from the usual 60 Hz to 120 Hz, 240 Hz and beyond. While 240 Hz consistently offers better motion performance than 120 or 60 Hz LCDs, the law of diminishing returns cuts in above this, with higher refresh rate displays offering less of an improvement.
The latest technological advancement in the LCD space is the use of LEDs as a light source. Previously, all LCDs used CCFL (Cold-Cathode Florescent Lamps) as a light source. These were similar to the florescent lights used in offices, bathrooms, kitchens, etc. LEDs, though more expensive, are more energy efficient, and can offer better color accuracy. There is no such thing as an "LED TV" in the home, those marketed as such are merely LCD TVs with LED lighting.
In addition to flat screen HDTVs, LCDs are used in everything from calculators to front projectors.