Believe it or not, functional home designs and modifications are making a comeback. Good article at the Realestatejournal discussing new home designs. One of my favorites is the tankless water heater.
While you most likely would not recoup the cost of the more expensive water heater were you to turn your house around quickly, the cost savings would be nice.The Fresh Air System is nice as well. Several builders in the area are beginning to install Radon mitigation systems. This is a good idea not only for the radon aspect, but this also allows the house to breathe – houses are living systems that need that ventilation.