Right now we need to pull together, mourn our dead, and help the survivors as best we best can...donate blood, I'm sure the supply is dangerously low in the NY area already.
The best way for this country to retaliate is not through violence. The sun will still rise tomorrow, we will still be Americans, we will still be proud, we will still be a democracy, and most importantly we will rebuild (hopefully even taller and bigger towers).
To Those Who Did This:
Whatever the reason for this, it doesn't matter, you have not crushed our spirits, we will still prosper now and in the future, and we will always be free men and women.