At 8 ft. 50 inches will be huge. We have a 42" in the bed room on the wall and its 10 feet from the end of the bed and it is plenty big. I know bigger it better but save a little and go a little smaller. Personally, I am a big fan of Samsung and they usually get you the most for the money.
Not sure where you are in relationship to large electronics dealers, but remember to price compare and haggle with the sales people. The sticker price is negotiable, and most stores including Best Buy will come down on their price to keep your business if they think you can get it somewhere else for cheaper.
