How high to mount my TV monitor?

It is 6 feet to the center of the screen. When I sit back in my couch I am looking directly at the center of the T.V..
Not many people sit with their back vertical to the floor so this makes sense to me.The 13 feet is from your eyes when lying back on the couch.

I think that putting a TV above the fireplace is one of the great examples of "interior decorators" putting form over function. Maybe it looks pretty for photo shoots for magazines, but I have never been in a room with such a set-up where I didn't have to look up, and within a very short period of time, I start to feel the strain in my neck.

However, what I think doesn't matter a rat's butt, or so people tell me from time to time. So all I can say, give it a try, and if your neck still feels fine after watching the Star Wars or Lord of the Rings trilogy, then go for it.

Of course, a Lay-Z-Boy recliner would solve potential problems too. Get one with a cup holder for beer, ...and a pocket for your remote(s).

Sold! Or rather, unsold! Thank you all for your gracious guidance. Based on this, I have (ahem) shelved the idea of the over-the-fireplace screen. It would end up being quite a bit higher than the one described by Telemark. Oh, and Markphd, I will be stopping by the Lay-Z-Boy gallery this week; maybe I can pick the couch up there as well.
Marty

Actually, the proper height should be when you are looking at the screen your eyes are level with the bottom 3rd of the screen. Unfortunately this is not practical in most theater setups.

If you're going to mount something, I suggest you choose something other than your TV monitor (ha ha)...