CNN ran a very interesting series of 13 articles written by a pretty smart group of folks, each with his own perspective on the current turmoil in the financial markets. The series includes articles from Warren Buffet, Treasury Secretary Henry Paulson, and Ben Stein, as well as the heads of a number of large financial institutions.
The consensus seems to be that we're in for a rough ride for some time to come.
My conclusion is pretty much aligned with that of Ben Stein: invest in indexes and ignore the ups and downs of the market. Still, while I will continue to hold onto my existing investments indefinitely, I will not be putting any new money into the market (expect my 401K contributions) until some measure of calmness returns to the markets.