One of my winter projects has been planning and installing Lutron RadioRA lighting controls through most of my house. RadioRA is a fully programmable system that uses RF (and over existing wire) communication to automate lighting throughout an existing house. It's more expensive than wired systems, but the cost to cut into all your walls, wire, patch, and repaint makes an RF system more than worth it for existing homes.

I found the cheapest deal for new components from Davis Wholesale Electric, and bought a few additional from eBay. The first three took me about 2 hours to install and I had to strip down an old 50+ foot telephone cable to do continuity testing between multi-location switches. The rest should go start to go faster now that I have the system down. Haven't installed or programmed the master controls, though I did test the system w/ the flashing mode which is extremely annoying when all the lights in part of your house start flashing one after another.