Account for time (Score 3, Informative)

I do high end low voltage installations for a living. And while most of the hardware is insanely expensive, the same results can be achieved with commondity equipment and open source solutions.

That being said, pre-wiring is the most important aspect of what you will be doing. Depending on your budget you will want to wire CAT5 (or 6e) into all light switch and telephone locations. At a minimum you will need CAT5 to every video location.

Wireless technology is too dependant on outside factors to be reliable. Good old copper gets the 1s and 0s to the correct place much more efficently. Plus, if it's called for, power over ethernet doesn't work very well wirelessly :) CAT5 isn't just for bits and bytes any more. It works great for remote thermostat sensors, infrared transmission, etc..

While we install touch panels by AMX Corp. the same thing can be done with a cheap touch overlay'ed display, PXE, and VNC. I would recommend staying away from X10 products. If you don't want to spend the time to write your own control software, the NetLinx programming language (used on AMX products) is easier than learning QBasic. Some of their controllers show up on Ebay for reasonable amounts.

The single most preventative aspect of this project is the amount of time involved. We will spend months in design, prewire, install, and programming on even relatively small systems. But if your wiring is not in place, no amount of time spent will be as productive.