The National Association of Home Builders reported in McPaper that the size of new McMansions in the third quarter shrunk to 2,438 square feet from 2,629 in the second quarter. If you do the math, that's the equivalent of a 200-square-foot den.

In some households, I guess that could be a crisis. But how much house do you really need?

In 1973, the last year for which the average household had a full three residents, the average new home was 1,660 square feet, according to the the U.S. Census. That's plenty of room for three bedrooms, a couple of baths, a living room and a kitchen you can eat it. But by the second quarter of 2008, the average size of new homes had ballooned to 2,629 square feet. That's 969 square feet more -- a good size one- or two-bedroom apartment's worth of additional space to heat and cool and store junk in. Meanwhile, the average household in 2008 had only 2.59 residents -- two people and a good-size dog.

New homes in the coming decade will be smaller and closer together, predicts Virginia McAlester, author of "A Field Guide to American Houses." Interviewed by the Washington Post, she says the high cost of building and maintaining roads, sewers and utility lines will discourage suburban and exurban development, while declining discretionary income will make huge, expensive-to-maintain houses unappealing. She also predicts that in some areas large suburban houses will be converted to multi-family homes because they are unsustainable by a single family.

I can practically hear the neighborhood association meltdown the first time that happens. Mr. Wilson, who lives across the street from me, will be organizing the militia.