I think 8 years has provided a bit more historical perspective on this event, and America's predictable over-reaction is really more significant than 9-11 itself. Not that it wasn't important. It was a wake up call, but the United States was tuned to the wrong station.
America didn't over-react. It'd be almost impossible to over-react to 9/11. America reacted incorrectly
If 9/11 had happened almost anywhere else, it would have been just another day in the life. But okay, I'll refrain from debating this.