I agree that the practical issues, like skimmer height, are important when deciding stand height. But the viewing experience is paramount. The most important species is YOU. Measure the height of your eyes, when on the couch, in your favored position. If you want to see the bottom of your tank, you need it to be below your eye level.
I watch my tank from a couch as well, and I wish it wasn't three feet high. Two would be better. Find the height that gives you room to work underneath, and is low enough that you can see the whole tank from the couch.