In the article linked below, Jeffrey Goldberg gives the painful details of how our airport security is nothing but a sham, "security theater", as he calls it. He lists the many items he was able to get through security, undetected.
http://www.theatlantic.com/doc/200811/airport-security
In my opinion, the only real security improvement since 9/11 is the mandatory hardened cockpit doors. The random security screening and the forced removing of shoes just make flying a little more dreadful, in my opinion.