Sometimes we leave a light on across the other side of the room near the bar area. Not sure I would like having any other lights on in the immediate HT movie watching area, possibly behind the seating if any. Since my back wall is flat black and my side walls/ceiling are a nice dark blue color, I hardly get any stray light from the projector beam either.
You would not want the picture to suffer, but I don't think ambient light in other locations of the room would hurt, especially during a Super Bowl party or whatever.
