Owning a home is the original American dream. It's the old frontier spirit, wanting to claim your own tuft of the New World. Then again, these days it also makes perfect economic sense. Experts estimate that all of the homes in the United States alone are worth a combined $14 trillion. That goes a long way to explain why a housing boom has been sweeping the globe. Where there is a boom, though, there may be a bust. Read any headline from your local newspaper, and you'll se