Do We Need Wall Street?

http://www.newyorker.com/reporting/2010/11/29/101129fa_fact_cassidy?currentPage=all

This is a long read but it does an excellent job of describing how Wall Street has evolved from a system that creates value by allocating funds to their most productive use, to a system that makes most of its money by making bets that provide little social value but huge benefits for bankers.