Monkey Man, that is really cool!
Some things we learned from having a house built for us, about 3 years ago:
1. Have Cat 5 lines pulled to each room than you think you'll need. We had only one per room, and in a couple places, I really wish we'd have had two (or more). One for phone and one for internet. Wireless is great -- when it works!
2. Makes sure there are enough lights outside, and enough switches. We actually ended up with some exterior doors that don't have switches for outside lights. Dumb.
Insteon to the rescue, but it would have been nice not to
have to go that route.
3. Get a record of where all the wires are pulled. Take pictures before the wall board goes up, e.g.
4. Follow the progress of construction as closely as you can. Pay attention to details. Believe it or not, we actually caught a framing error, before it was too far along (no wall board): the back door was missing! I kid you not! They put a window there instead. Fixed it, of course.
5. Got a theater? Was it designed and built by a specialist? Ours wasn't. Our builder had never done one before. It turned out pretty nice, but little touches that a pro would have thought of would have been icing on the cake. I see pictures in magazines, and say "next house"!