I predict that those who expect a pricing bottom in 2009, 2010, 2011, and 2012 may all be correct.
It will happen in different areas and different market segments at different times. Also, the bottom of the cycle typically results in very stagnant prices.
That said, I think there will be plenty of good buying opportunities starting as soon as late 2008 or 2009, and continuing for several years depending on the area and market segment.
