I would say the response was right, but the tactics employed after the conventional aspects of war were incorrect.
Was it right to go to war with Iraq even though technically most of the terrorists were not from Iraq? Yes. Saddam should have been taken out of power a decade earlier anyway.
We should have gone to war with Saudi Arabia, though, and bombed them just as hard as Iraq. Instead, what we did was sort of like arresting or killing the accomplices, while letting the masterminds and source of the problem go free.
Unfortunately, Osama Bin Laden was just one man and one mastermind/charismatic terrorist leader. Sadly, he will be replaced in time by another, and the cycle will start all over again. Until the west grinds radical Islam to non-existence, this problem will continue to resurface.
The difference between them and us is we only do it because we were provoked by many terrorist attacks, not just 9/11, that just put it over the top, and we said "Enough. Time to pay for your crimes." On the other hand, they do this allegedly in the name of their false god, or at least certainly a false interpretation of "God," for no good reason really.
Yes war is justified, and assassinations of all radical muslims, not just Al-Quaeda members, whenever and where ever possible, is more than justified.
They want to use "God" as a standard of judgement, here is the commandment of the allegedly the same "God" they claim to be serving:
"Who ever sheds man's blood, by man shall his blood be shed..."
It's one of the oldest commandments in the Bible and Abrahamic faiths.
But anyway, for the urban warfare aspects, we should have kept infantry use to a minimum, and rely on more special forces type stealth kill missions and assassinations for top terror organization members.
Also, I think Gangs and organized "mob" crime in the U.S. should be considered illegal militias or pirates, which the constitution addresses, and they should be prosecuted via war and the laws of war. The only technicality that distinguishes a gang from a pirate is the fact that the traditional definition of piracy requires members of one boat raiding another by violence, or members of a boat raiding land by violence. Gangs often do the exact same thing to one another, or to bystanders on land, just without boats. Some mob violence and other mob activities meets both the definition of illegal militias and the definition of piracy.
People who commit mass shootings or bombings should be prosecuted under the laws of war, not the civilian laws. Terrorism in general including any mass shooting or mass bombing of purely civilian targets, should be considered an act of war, whether or not the perpetrator was a member of any state's military. The perpetrator should be tried as a war criminal under military tribunal.
People who intentionally massacre unarmed civilians deserve no mercy, nor do they deserve the priviledge of plea bargains or other such measures found in a civilian court system.
I know it's off topic, so if the admins want to delete this, fine, I'll put it in my blog instead.
But it IS 9/11 rememberance day after all.