Left up to me I could live in a 1000 sf house so long as it had an attached 6 car garage.
But really...how much house does the average family need? Wife and I recently purchased 4br/3 ba house...a little over 3000 sf. At one and the same time it seems big enuff for us and the twins...with stepson coming home from college every once in a while. Then again it seems too big at times (like why am I heating/cooling rooms when I can only be in one room at a time?) yet I can see it beginning to fill up.
Aside from price considerations, what is the ideal size house for you and why? Do you have to entertain at home? Frequent family o'nite guests? Mother in law staying with you? Need to impress your peers?