[quote author="Daedalus" date=1229932394]I believe CS indices are already inflation-adjusted. For a market to match inflation, its curve would be a straight horizontal line. LA has about 45% to fall from current prices to reach "par" value. Irvine would probably have to fall a little more than LA.</blockquote>
Nope, Case-Shiller indexes are in nominal, not real dollars. Here it the CPI-adjusted Case-Shiller for the LA/OC MSA through September 2008:
<img src="http://www.ipoplaya.com/casecpi0908.jpg" alt="" />
To get back to zero, i.e. home price appreciation = CPI, it would mean prices need to head down another 35%. This is based on prices and CPI from Jan 1987 forward.