From Reuters yesterday:

MONTREAL (Reuters) - Former U.S. Federal Reserve Chairman Alan Greenspan said on Friday that he does not expect another "bubble" in world markets for a long time, and that central banks at any rate do not control the long-term interest rates that can be related to bubbles.

Greenspan didn’t see the dot.com and housing bubbles coming, and never admitted that his policies may have played a part in them. It’s unlikely that he’d see any other bubbles forming either- like say in commodities.