Gene Fama - the person credited for developing the efficient markets theory - talks about whether or not markets are still efficient and whether the efficient markets theory still works.
His main points:
1. Of course markets are still efficient.
2. Even professionals cannot time the market. (In other words - buy index funds)
3. Although he prefers less regulation, the concept of banks being too big to fail is a problem. TBTF occurs because the government cannot let a huge bank fail because of the risk to the financial system. In essence the government unwillingly gives a guarantee to the bank. His solution, which is one I have also mentioned before, is to increase capital requirements. He wants huge capital requirements - 40% or more. In this case government regulation is needed to combat this TBTF problem.