Welcome to the forum
I own a DLP ... beside the characteristics you mentioned (contrast, resolution, etc.) you need to consider the size of the TV box, my DLP is like 14" - 16" thicker compared to 3" - 4" for the plasma or LCD
... if your room is small, I think is better to get a Plasma or LCD.
You mentioned a viewing distance of 8.5 feet ... so I'm assuming you already measured the room, that distance is from the wall or you already considered the thickness of the TV??? ... another thing you need to consider is the placement of your seats, you can't seat to close to the back wall ...
I think you can get a bigger DLP for the same price of a smaller LCD or Plasma
Good Luck.