Hi, The definition and the quality of the material being showed play a huge role. On some material you can't be far enough. However with good quality HD material you can be very close. In fact, much closer that it is usuaally recommended by these sites and software. What is the benfit of getting a large display if you need to move back keeping the same ratio for the portion of your field of view being occupied by the video display; it does not make sense.
For my 150" diagonale 16:9 screen I sit only 14 feet away for HD material (TV & Blu-ray).
