It was much than just 19 hijackers. It was an unprecedented attack on our soil by foreigners, loss of thousands of lives, billions in lost revenue, and the loss of our sense of security. In other words, a near picture perfect act of terrorism. I certainly view it as a world changing event. I think the entire world was captivated too. We are the biggest kid on the block. We were taken to our knees, at least for a day, by a handful of animals.
Oklahoma City was carried out by three guys. One is in prison, one served time and was released, and one is dead.
Those are good points but 9/11 has changed nothing: assassins and terrorists have always walked amongst us. The only reason that the 9/11 attacks was a "near picture perfect act of terrorism" was b/c of Bush's predictable reaction to the attacks. The terrorists were counting on Bush to change our way of life while improving their own standing in the world and he played right into their hands.
Thanks to Bush, we have a president that violates the constitution on a regular basis (FISA, signing statements, illegal wars), we have the US's reputation in tatters--we torture people and invade countries with no legal justification, we can't take hair gel on an airplane, and worldwide terrorism has grown exponentially etc.
It's not the terrorists that did those things on 9/11. It was the Bush administration's response to 9/11.
Terrorists do terrorism to affect a change in the political climate: to that I'd say MISSION ACCOMPLISHED!