Originally Posted by goosedown
For Plasma televisions, the advantages over LCD, are Better contrast ratio, better ability to render deep blacks, more color depth, better motion tracking (response time), and more availability in very large screen sizes.
Contrast ratios reported by the manufacturers are just numbers these days, generally derived by whatever method makes their display sound better, so I would not rely too much on what a manufacturer says their contrast ratio says. Since contrast ratios are measured as the difference in light emitted at 0 IRE (black) and 100 IRE (full on white) what is more important is what is the light output at 0 IRE.
In general I do think it can be said that plasmas will produce less light output at 0 IRE than a LED thus producing a blacker black. However, lately there have been some disturbing reports that the new Panasonic plasmas have employed an automatic circuit to offset the panels natural tendancy to dim over the years of use. While in theory this would make the time when the panel drops to half life dimming longer, thus improving the panel life span hours, they apparently have been way too aggressive and there are reports of some plasmas actually emitting more light at 0 IRE than LCDs! For more info on this with Panasonic's reply so far see: Panasonic admits plasma TV black level change but says picture quality still 'excellent'