Should I wire my home for AC or DC loads?

It depends on the size of the system and what type of loads you want to run. DC appliances are usually more efficient than AC since you don't have to worry about the loss through the inverter, but DC loads are typically more expensive and harder to find than their AC counterparts. Small cabin and RV systems are typically wired DC while most home systems are wired for AC loads exclusively. With improvements in inverter efficiency AC is the way to go for home systems. Another advantage AC has over DC is that the voltage drop for a 120VAC circuit is much less than a 12VDC circuit carrying the same power, which allows you to use smaller gauge wire.