Also on a somewhat related issue we are also long over due for a commerical airline disaster. The last one was in November of 2001.
Al Qaeda is plenty busy in Iraq and Africa and Asia. They are fighting our citizens in Iraq and Afghanistan...remember that...they might be in uniform...but they are still fighting and bombing on a daily basis.
As for a domestic attack?...it is surprising indeed that we have not had one...considering how simple it is to obtain guns and explosives through theft and the black market.
All they need is to simultaneously attack shopping malls or schools and the landscape and face of this nation will forever be changed and never the same again.