Buttonwood thinks this might be a good time to bet against pessimism:

Lombard Street Research now argues that the US market has only been cheaper for 26 months in the last 140 years. Those months occurred in 1920-21, 1932, 1942 and 1982. Two of those periods reflect the effect of world wars. Of the others, one was the great depression and the other the aftermath of the inflationary 1970s.

Since I hope to be able to retire in the distant future, I'm buying stocks soon.