DISADVANTAGES of LCD vs Plasma televisions include:
1. Lower contrast ratio, not as good rendering deep blacks.
2. Not as good at tracking motion (fast moving objects may exhibit lag artifacts) - However, this is improving with the recent implementation of 120Hz screen refresh rates in higher-end LCD sets.
3. Not as common in large screen sizes above 42-inches as Plasma. However, the number is growing fast, with 46 and 47-inch screen sizes becoming more common, and some LCD sets having a screen size as large as 65-inches now available to the general public.
4. Although LCD televisions do not suffer from burn-in susceptibility, it is possible that individual pixels on an LCD televisions can burn out, causing small, visible, black or white dots to appear on the screen. Individual pixels cannot be repaired, the whole screen would need to be replaced at that point, if the individual pixel burnout becomes annoying to you.
5. LCD televisions are typically more expensive than equivalent-sized Plasma televisions (although this is changing), especially when comparing EDTV Plasmas to HDTV-LCD Televisions.
That was taken from this site:
http://hometheater.about.com/od/lcdtvfaqs/f/lc dfaq2.htm