Why do you like having a giant house. I've never had this feeling and would like to understand. (I currently live in what I would consider a reasonably sized apartment in SF.)
Parking. My own fenced in yard to BBQ, dog to run, kids to play in (if I had any). Tons of space to put furniture, exercise equipment, etc. My own garage to park in. Ability to easily have dozen+ people in my house for gatherings, etc. Think of it like hard drive space or RAM :-)