Plasma has the most natural picture and best viewing angle. Although viewing location is not quite as critial as speaker placement, you may consider placment in front of the fireplace using the table stand. Above the fireplace installs look nice when the television is not being viewed with programing but the best TV viewing location is close to eye level. That being said, if you do consider my suggestion, the new LED backlit LCD's are extremely light in weight and can easily be moved by one person if a fire was desired on a cold winter night.
Buy LED, LCD or Plasma
Going for a new TV. Any hints, warnings or advice? It will go over the fireplace instead of the rug there now.