In that you say the USA is the only remaining post-Cold War Superpower.
Superpower or not, this isn't going to help you any as far as terrorism goes. I don't mean that in any disparaging sense...it's just a fact that terrorism can strike any target anywhere at any time. All the Minuteman, Trident or SS20 ballistic missiles in the world can't prevent a fanatic rogue nation or religeously motivated individual from wreaking havoc if they so choose.
As you say, the world has changed and certainly not for the better. The Coalition forces 'won' the war in Iraq, but have NOT won the 'hearts and minds' of the inhabitants. Perhaps they are glad to be rid of President Hussein, but that doesn't take away their anti-Western feeling, as can be seen fron the ongoing attacks against US and British Forces. Dissident Iraqi factions in the last three days have targeted two oil pipelines and the main water pipeline into Bagdad. To what end? Pissing off the coalition maybe, but costing their own people $7million a day in oil revenue and depriving 750,000 of their own people of vital water.
This is the difference between war and terrorism. Even if your own people suffer, the end justifies the means in the minds of the terrorist. If a country goes to war, as Britain did against Argentina in 1982, it is usually to counter an act of aggression or claim against its territorial possessions. That has justification in International law. The Iraq conlict had dubious justification, but a general consensus was reached by the UN and the action was legitimised to some extent. Acts of terrorism by their very nature have no justification other than in the minds of fanatics and the accepted 'Rules of Engagement' no longer apply.
What makes it difficult for nations like the US, Britain and other 'upright' countries is that we have to throw away the rule book and wake up to the fact that these fanatics have no way of gaining their demands by 'legitimate' means, so will use any and every dirty tactic to leverage their views. Unfortunately, as 11/09 proved, we can't forsee every eventuality, unless we stoop to 'their' level, and that, my friends, is an impossible task.