Let me first begin by saying how sorry i am about whats happened. This sort of thing should only happen in the movies. I've a cousin that lives in NYC and he's ok but many, many others are not.
Regarding revenge, could i suggest that the guilty parties be brought up on charges of Crimes Against Humanity in an international court, presided over by an international community of jurrors and judges. It is one thing to be held accountable by your enemy and another altogether by EVERYONE! This i think would minimise, if not eliminate, retaliation by the guilty parties.
Regarding the dancing-in-the-streets by various people, i view them with pity. Their hatred has so blinded them that they cannot see that Americans are people just like everyone else. It is this hatred that must be ultimately fought. It is there that suicide bombers are born. Eliminate the hate and the Bin Ladens will vanish.
Again my deepest regrets go out to all of you who have been hit by this tragedy.