I found a desk sold by Ikea that had an electrical motor to raise and lower it. I could sit on a swiss ball or a chair, or I could stand. I chose to stand a lot. It was awesome.
Ikea discontinued it, and when I moved out of the DC office for SF, apparently there was a near knife fight to claim it. Of course, the director of Operations won.
I've always thought that desk would be a perfect media center, since you could raise it when you were not going to be planted in front of the tv, and lower it when you were going to melt into the couch.