My latest Street.com column, "A Not-So-Efficient-Market Hypothesis" is up at RM.
It expands upon many of the ideas from earlier comments, Compare and Contrast.
UPDATE: December 2, 2004 5:43am
Interesting article in the New York Times about surprising price patterns and inefficiencies in the Fine Art market:
Economists Have Advice for Buyers as the Art Market Heats Up