The End of Wall Street's Boom - Portfolio.com
One of the best articles I have read on the fall of Wall Street and why it fell. It actually made sense of what was happening and why, and why it shouldn't have been happening in the first place.
Update 12-15-08: there is some good Hacker News commentary sparked by this Dilbert.
Update 12-18-08: Henry Blodget wrote a great article on why Wall Street always digs a hole for itself.