Dr. Chung
Why mix inches with metric? You seem to be suggesting a viewing distance of about 2 to 4 times the width of the screen, which is in line with the usual recommendations.
I have a 36 XBR with a 30" wide screen, and would prefer being closer to the 2 times the width for viewing, but that is too close for listening with external speakers, and I want to be able to enjoy either stereo music or video without moving the chairs, so I let good stereo imaging drive the viewing/listening distance. I do not use the center channel for music. My front LR speakers, center to center, are about 7.5' apart and 3.5' from the wall behind them, in a room 14' X 19', so my viewing distance is about 9', or 3.6 times the width (3 times the diagonal), which I consider a bit too far for an enveloping video experience with progressive scan movies or HDTV.
I suspect 9' may be too much separation for Chad's 30' wide (36 XBR?) screen. My audio system, even with stereo music, generates a soundstage that dwarfs the video from the 36 XBR, so I plan to move to an 80" X 45" front projection screen, where 9' would be 2.4 times screen height (1.35 times screen width).
db