For me, apart from the many conspiracy theories (which I approve of MANY, because they make more sense the the crap the media tells us) there is ONE reason why I believe that it was staged, or known, or wtv you want
And it's this :
http://www.youtube.com/watch?v=Rg5NvKpJfKE
The US protocol (Actually, the protocol of pretty much every democratic country in the WORLD) in case of a terrorist attack is to immediatly hide the president and assure it's protection until it is confirmed that the attacks are over.
Why did bush stay calm, heck why did his security agents leave him there?
How in the world did they know that bush was not the target of the attacks?
Normally, they cannot know, and this is why the protocols exist, and the president MUST be moved to the nearest bunker.
Only this time, they were 100% positive that bush was not the target.
Strange.