Remember, 9/11 was not about attacking 4 planes or the passengers therein, but it was about attacking the icons, the symbols of part of America.

Icons and symbols within a society to which you are opposed can cause more damage to a populace than attacking the populace. For instance, suppose rather than piecemeal attacking muslim lands, we just drop a bomb on whats left of Mecca? The act of destroying it means nothing to us but would inflame and hurt millions. The only difference between one culture and another in this case is just how long they remember such things in the forefront of their everyday lives. 9/11 is over, and while we still have a big whole in the ground we've moved on. Were we to destroy such an icon as Mecca, for 1000 years they would remember it every day.

My .02