When I had children of my own, we converted our two-and-a-half car garage to a den - an awesome set up in that it was cavernous, and the door which separated the garage from the rest of the house was an external door, sealed, and nearly soundproof. This was where the only television in the house was, as we all shared it, and it could be used just as easily for adult activities as it could children's.
Moving to Saint Louis was an experience insofar as our house was very small. During our tenure there, we tried a variety of combinations, none of which were ideal. The master bedroom moved an unprecedented FOUR TIMES. And, thanks to galinda822 and her 27" television, there was a TV each of the children's rooms, the common area, and the living room. Still - when we built out the basement for the children, they wanted to be upstairs, and when we moved into the basement, they wanted to be downstairs. A small measure of advice for new parents - they always want to stand between you and your television, no matter where you are.
Back in Texas, we gave the children the entire South Wing of the house. Nearly one-third of our spacious home is dedicated to the children: Two bedrooms, a full bath, and their very-own living area. This has worked great except for one small oversight: To get to or from that area of the house, they have to fully traverse the remaining square footage. Hrm.
So my wife decided on turning the master suite into a 'Hotel Room' with leather chairs, a small table, and flat-panel television. I picked up the TV today. My first HDTV.
I'm turning into my parents.