Oh yeah, SirKit has some awesome ideas for active solar water heating. He's designed what he believes will be an vey efficient collector that will be able to heat the pex tubing from several angles so that the collector doesn't have to move to follow the sun. As the water runs through the pex tubing, it will collect in an underground pool which will stay hot because we'll insulate it. Through that pool will run more pex tubing which will carry the potable water that comes from the city water supply to the water heater. By the time the water reaches the heater, it will no longer be 55 degrees or so, it will be more like 90, so that we won't have to pay for so much natural gas or electricity to bring it up to the temperature needed for use in the house.
We found a manufacturer that makes metal roofing with photovoltaic cells inbedded in the material. Haven't found out how much it is, but photovoltaic is still too expensive for full conversion because of the cost of the panels. When they come down in price, the return on investment will be more reasonable.