Jeremy Siegel
The "Wizard of Wharton" and author of the investing classic Stocks for the Long Run still generally sticks to his buy-stocks-and-hold-on-to-them guns. But he has come around to the argument that price is a major determinant of long-run returns. Buy stocks when they're cheap and you're better off. Right now, Siegel thinks stocks are reasonably cheap.
Key Stat: 6%
Siegel's estimate of the current yield on stocks, as opposed to the 1.79% risk-free yield on inflation-linked bonds known as TIPS