NEW YORK (Fortune) -- For the past five years, the housing bulls have been trotting out one rational-sounding argument after another to explain why the boom made perfect economic sense. Forget about a crash, they assured homeowners. Expect a "soft landing" where your three-bedroom colonial in Larchmont or Larkspur not only holds onto its huge price gains, but keeps appreciating at a "normal," "sustainable" rate of 6 percent or so into the sunset. Real estate slowdown New homes slump worsens Pace of new home sales falls more than forecast as inventory builds, prices decline. (more) Freebies for home buyers Home...