I'm a purest. 5.1 should be presented in a 5.1 format even if you have a 7.1 system installed. Same thing for aspect ratios. No cropping in my HT. 2:35:1, 1:85:1, 1:33:1....all constant height.
The only thing that is upscaled in my screening room is the OPPO making a DVD look more like a BD...