As reported in MinnPost.com, housing researcher John McIlwain has predicted that the period of suburban sprawl is over, and that more Americans will be pushing to live in more urban (one could even say "walkable") suburbs. "[A] combination of economic, demographic and regulatory trends over the next decade will create 'a new normal' in housing markets across the United States," as spurred by four key demographics: older Baby Boomers who move to more urban areas (even if not the "big city"), younger Boomers who will be tied to suburbs by the inability to sell their suburban homes because of the "soft market," the Millenials (children of Boomers) who are unable to find steady employment and thus will be forced to rent longer than earlier generations were expected to, and immigrants who need space for large families. The need will therefore be to make more of what currently exists rather than building further out.
We are already seeing some of this in north Jersey, where people who moved to towns like Montclair in the 1970s and 1980s are being priced out and moving instead to smaller towns like North Caldwell. North Caldwell has already begun to adapt to this new wave of Boomers. Other towns are starting to see demographic shifts due to a rise in immigrants. Many lower-middle-class residents are unable to live in the towns they work in, and some of the smaller suburbs are benefiting from this regular stream of homebuyers. Towns of all economic backgrounds will start to build up their "urban" centers, and those areas will in turn act as a draw to newcomers who want to live a more ecologically friendly life but not in a major city.
A good history of the American suburb is Columbia professor Kenneth T. Jackson's Crabgrass Frontier: The Suburbanization of the United States.