What’s the best kind of flat screen tv I can get for my money’s worth?

Ok, so we have this ancient Panasonic that we've had for AGES and we're just waiting for it to break for us to get a new one. My dad wants to get a flat screen next time we get a tv, but we're not sure which kind we should get. What's the best: LCD or Plasma? How long do they usually last? Which is better quality? What's the difference? What's the best for our money's worth?

We've been looking around, and he wants to get a 52" flat screen that you can mount on the wall.

Thanks for any help, if you need anymore details just ask