distance between standard sitting distance & TV might be the more important thing. To close & you could save over 1/2 by getting a smaller tv. To far & you're to far away & should move closer.

A friend of mine has a A/V company which does installations of home theater systems, one of his most frequent gigs is going into a home and lowering and /or moving a previously installed screen, "looked nice up there but everyone in the house has a sore neck"

The same viewing distance rules that applied to old standard definition TV do NOT apply to HD TVs. The reason that we used to sit so far back from an SD TV is that it looked like crap and we needed the distance so we wouldn't see how bad it really looked. HDTV is different, the picture is so clear and detailed that you can get away with sitting much closer. I sit about three feet away from my 42" display in my office and about 10 feet from the 60" display. And, yes, place it at eye level.

For distance from the TV there are several recommendations - the most common of these are twice the distance of the diagonal size of the TV. I.E a 32" TV should be viewed at 64" (roughly 5ft.) away. Digital Flats panels can in fact look worse when viewed too than the old Tube TVs. The digital distortion becomes much too apparent. Thus the distance is needed.

... I never cared about distortion or what not... I care more about me having to move my head to see the picture.

Actually read the manual. It tells you how far, what angle, etc.
JJK

As for how high? Same as for computer monitors. Assume your normal viewing posture and the screen CENTER should be 15 degrees below horizontal (VESA recommendation). My unit is a 50 inch diagonal (49.7) and the base of the stand sits on a 25 inch tall table. Ideal for good posture, but not quite for slouchers. If it had no stand and were 2 - 3 inches lower it would be perfect. Also note, we have a FENCE around it to keep the 3 year old away from it. Could be fatal if he tips it over. We have it reinforced 4 ways from Sunday to avoid that.

As for the distance, it varies from maker to maker. My Panasonic Plasma setup guide recommended from 3 to 5 times the diagonal measurement of the screen. If you don't like swinging your head from side to side, it recommended toward the 5 times distance over the 3 times.

I don't care what anybody says, 5 times the diagonal measurement is WAY too far. That means that you should sit 17.5 feet away from a 42" TV or 25 feet from a 60" TV? This is UTTER NONSENSE! At that distance the human eye simply can't resolve any of the fine detail of which an HDTV is capable. All you will have purchased is screen size, not increased image resolution.

Even at 2 times, you might be moving your eyes a bit just like in real life but certainly not swinging your head all over the place. Part of having a 16:9 screen and sitting closer is that the increased width of the image partially fills your peripheral vision and contributes to being immersed in the program. It's the difference between "you are there" vs. "it's way over there."

bigger TV's are meant to be viewed farther away, not closer up. (just like brighter lightbulbs are meant to fill up larger areas) That's why if you want to sit 6 feet away you get a smaller TV. If it's an HD one, you get a higher res one.

The best distance for watching true (not up-scaled), high quality 1920x1080/25p at 100 Hz refresh rate on my Panasonic Viera 50" plasma set is 2.5 - 3 meters.

And I may be well over 50, but my eye sight is still as sharp as it's always been.

i'd sit anywhere in front of it if there was anything worth watching on it......

ok, back in my box......

I appreciate all the input. As far as the distance the TV should be above ground, I gather the middle of the TV should be at the eye-level when sitting comfotably on the sofa. Am I right? any other suggestions? Thanks again. you guys rock.

THX have a set of broad guidelines at: http://www.thx.com/home/setup/display.html

Looks like THX is backing me up.

The 5x of diagonal distance is the OSHA recommendation. I don't believe it's appropriate to apply to home theatre. Most people don't even have rooms that large.
However, the OSHA recommendation WAS heavily used in the arguments for adopting the 720p standard in EU.

Looks like THX is backing me up.

THX has an acceptable guide to setting up a TV. Acceptable as the guide that comes with new video cameras telling you how to hold it while shooting. I don't see anywhere in that guide what to do with the dresser or computer, or how to compensate for when we're sitting up in bed vs lying down. Or what to do with everybody still broadcasts in 4:3 anyway!

"what to do with everybody still broadcasts in 4:3 anyway?"

Why that's easy - you just stretch it all to fill the screen. Everyone loves short squat people. Besides, hate to waste all that screen real estate you just bought.

This is my pet peeve. All the hotels are finally getting on board with nice flat panels yet they insist on locking the user setting to "stretch." I find it insulting that they think we prefer to see a 4:3 image stretched like that... and to lock the user out of the ability to change it to their own preference adds injury to insult. Geesh... at least they could use a smart stretch but no. Are the people in charge of setting up those TVs that dumb? or do they blindly follow the orders of the hotel buyer who doesn't even own a flat panel at home? [getting off soap box now, feels better]

Probably 90 to 95% of what I watch off-air and off-cable is 16:9 HD. "Everybody" is NOT still broadcasting 4:3.