Build it and they will come: The official site of the National Association of Home Builders offers lots of data and factoids on home-owners and home-buyers. From the home page, click on "Facts and Figures" to find information such as which areas of the country are the most and least affordable places to buy a house today (Rockford, Illinois, tops the most-affordable list) and how single-family homes have changed over the years. In 1975, for instance, just 20 percent of new single-family homes featured two-and-a-half bathrooms. Last year, that figure hit 52 percent. Central air conditioning has become a key feature as well, now in 83 percent of all new single-family homes. Other accessible data includes housing starts, materials used in home building, and home-ownership rates.