The easy answer... NEITHER! There's a revolution on its way... OLED technology will make both LCD and Plasma TVs look like a thing of the past.
The OLED (Organic Light Emitting Diode) produces brighter than any other back-lit technology and has the fastest response yet to signal changes. Technologically, they are lighter, smaller and more durable as well. They are also very good at taking abuse, so they can be used almost anywhere.
There are already cell phones and handheld devices, TVs, even keyboards where each key is a screen and many more prototypes that are introducing OLEDs.
We'll have to wait and see how this technology evolves, but its supposed to be 'the next big thing' in HDTV as well as many other applications.
Search for OLED Technology in your fav search engine and you'll get all the specifications and applications. Its very interesting.
Happy New Year! Itay.