I am reading the latest book by Jeremy Siegel that you recommended, and I am thoroughly enjoying it. He is a little bit stuck on extrapolating past experience into the future, but he presents some very interesting data.
By the way, I personally am beginning to believe that the mechanical "value investing" approach of investing in the low P/E stocks, as opposed to high P/E stocks, may have lost some or all effectiveness, as a lot of people jumped on this bandwagon.
I was reading an article about "statistical arbitrage hedge fund crash of 2007" and realized that a huge number of hedge funds are employing very considerable leverage buying low P/E stocks and selling high P/E stocks short. This cannot possibly be good for this sort of strategy.
By the way, true value investing is about more than mindlessly picking low P/E stocks as opposed to high P/E stocks.