One of the main reasons for this is that younger generations are more interested in living in population centers where they can walk to everything they need instead of having to constantly get into a car, said Salvatore Panto, mayor of Easton, PA, speaking at the recent Urban Land Institute Urban Marketplace conference here. "This is a generation that is looking back. They don't want to suburban four-acre lot," he stressed. "To the suburbs, I've got news for you: Look out!"

Of course, the revitalization of blighted downtowns takes time. In the case of Camden, NJ, a city with a bad reputation for years that has recently undergone a major transformation, the government worked closely with the educational and medical entities that already had a presence in the city, said David Foster, president and chief executive officer of the Greater Camden Partnership.

In the case of Easton, said Panto, government encouraged a flourishing arts, cultural and food scene to create vibrancy and attract downtown residential development. But the mayor of that city warned: "There's no 'one size fits all' when it come to urban places."

Mayor James Baker of Wilmington, DE decided to take the tough route in rebuilding that city's downtown. Since run down and vacated buildings attract crime, he decided to start fining the owners that refuse to tenant those structures. Fines vary from $500 to $10,000, and the city is starting to see an uptick in revenue collected from this program. In 2007 it collected $7,900, he said, and this year it is projected to reach $440,000. "I want to punish people who punish us," Baker said. "People have far too long taken advantage of these cities and people in these neighborhoods."

But Eric Menzer, senior vice president of Wagman Construction, which is helping the overhaul of downtown York, PA, warned that cities shouldn't just jump into projects proposed by developers and hope that they will attract residents and tourists. There needs to be a strategic plan in place that can sustain the development. "We need to try to transform the fundamental economics of these cities," he said, stressing the need also for outside capital.

To Wilimington's Baker, the future clearly lies in cities. And he didn't bother hiding his disdain for suburban life. "People have to go back to the urban areas," he said. "Suburban is just a silly idea in the first place. Cities are the only place human beings should be in."