A cursory glance through some pictures of new homes makes me notice that many of the TVs are mounted waaaayyyy too high...
I suspect the aesthetics took a big precedent over real viewing specifications...
The rule of thumb is quite simple:
The centre of the TV should be slightly lower than the eye level when you are seated. That way you are not craning your neck upwards, and this is quite unpleasant.
The most comfortable viewing angle is 12 degrees below horizon. As you move upward from there, fatigue and eye dryness increase gradually. Too high and you'll get a sore neck.
It is best to get it right the first time, and even if your ID or perhaps the lady boss of the home wants to center the TV around her eye level as she walks around, that's incorrect. And it's not a portrait, it's a TV, so sit down, take out the measuring tape and get it right.
This is a nice little article to help especially if you are good at DIY, otherwise leave it to the pros :
As for lighting:
From an article on CNET:
Room lighting Since most people turn down the lights to watch a movie, our recommendations are designed to deliver a better picture in rooms with controlled lighting. Unless you have a big-screen projector or you're sitting at the minimum viewing distance, you shouldn't watch movies in complete darkness--it can cause eyestrain. For bright plasmas and smaller direct-view sets, the ideal setup is to place a dim light directly behind the TV and leave the rest of the room dark. Look for special daylight bulbs that glow at 6,500 degrees Kelvin. You should also prevent any light in the room from reflecting off the TV, as glare will hamper image fidelity. Watching at night is best, but if you watch during the day, thick curtains will really improve the picture.
The key is to have some light, which does not add any glare or hotspots to the TV, but prevents your pupil from dilating too much.
Have a few lighting options, some bright and others dimmer, and add a
little light source that's close to your seat, so you don't have to get
up just to switch on the light to look at a remote or disc cover.
Here is a couple of useful links to the ideal lighting conditions:
I have no financial interest or other interests in any of the items / events I write about.