Following up on my characteristically brief post from yesterday, as Ryan says an additional problem with newer suburban and exurban development is that it is incredibly inflexible. Large McMansions can't easily be split into multiple apartments the way large urban homes have been over the years, and who knows what big box warehouses can be converted to other than warehouses. And from what I see whenever I head up 95, we already have plenty of empty warehouses. Inflexible zoning laws make conversion that much harder, of course, but even without them it isn't clear just how to repurpose some of this stuff.
Though despite my obvious preferences, I'm not actually one who thinks Great and Glorious Exurbia is going to disappear any time soon. Foreclosures and empty storefronts just might make it quite a bit less pleasant.