Plasma in my opinion is much greater. The only downfall is the heat. They produce a good amount of heat. But if you're in a cold area or heat doesn't bother you, it isn't an issue.
LCD screens (and yes, this includes LED TVs, which are just LCD screens with LED backlighting) are horrible for movies. Have you ever watched a movie on a Samsung TV and it looks like live TV? Usually, they have an option to adjust or "correct" this, but sometimes it comes out looking jumpy and stuttery. Samsung is the worst offender, which is sad because they're the most popular at this time.
I'm looking at snatching up a bigger plasma TV than my current 50" before they stop making them. Or hope that when they do stop, the price on them drops significantly.