^^^ Yeah, what he said. I used to have an 80" and sat about 8' away.. Still wasn't too big imho, but it was borderline too big for people not used to it. That's the trick, you get used to whatever size eventually
As for the center channel arguement. Technically, with a screen as big as these, I'd prefer to have a center channel on top/bottom. With a good center it doesnt' matter so much. My center is quite loud, 450watts so It's not like I can't hear it. Ideally, you want your center around the same plane and level as your front tweeters/mids. you want a seamless field of sound. My center is pointed in such a way that it points straight at my head when I'm sitting down. You do afterall watch movies either sitting down or lying down and not standing up. Their is a science to it. How high are your couches, how tall are you? Where's your head to basically. How long is the room? what angle the speakers are at is determined by the size of the room really.Heck even the height/shape your room and ceiling effects it all. You can go crazy with it if you want.
I never even considered a accoustic transparent screen. I did not want to sacrifice picture quality at all and they have a habit of doing that. Some of them even create a moire effect at certain angles. not to mention the really good ones can be very $$$$
