I've posted links to several critics of the new quantitative easing (QE2) that the Fed has started. I don't want to be too one-sided. So here's one from Fortune that shows how QE2 may help, How the banks can save Bernanke's bacon
The article suggests that the commercial banking system credit is key to economic growth and it was helped by QE1, and there's a good chance that QE2 will help further.
One thing that wasn't mentioned is that a lot of the money that's helping the banks is coming from the lost interest income of savers.