Some analysts suspect the initial housing bust could be just the beginning. There might be a second collapse in prices, as baby boomers start to retire/kick-the-bucket in their millions.
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/03/08/REDHVBQ2L.DTL
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/03/08/REDHVBQ2L.DTL