I'm only posting this to keep bearded men below the fold, but still, Atrios has a good point

It's true that as with many bursting bubbles, even if some people lose their shirts in the crash it's possible that left behind in the wake is something useful. However, it isn't clear that a bunch of extra modern housing is a 'good thing' even in a place where numerous people didn't previously have access to such accommodations. A house is more than a house, it's also a location. One thing that location needs to provide is access to gainful employment. Ghost cities might provide for some improved accommodation for people at low prices, if prices are going to drop, but that doesn't do much for them if there are no jobs nearby, no functioning government services, no retail, etc. And unoccupied housing units can deteriorate very, very fast. via

This isn't something we deal with so much in Austin, where the economy hasn't really crashed, or even stalled. But I've seen it in other cities: There's a real danger of suburbia turning from a middle-class milestone, like Dr. Jekyll into Mr. Hyde, into the new century's ghetto. People can move there and then be… trapped.