The cost of the war on terror, just to the US, is now estimated at over $5 trillion. I don't think it has been money well spent.
Bombing the shit out of people generally gives them a reason to feel aggrieved. As a result there are more terrorists now than when the war on terror started.
When the Twin Towers came down, George W should have come out and told the world that he was going to buy everyone in Afghanistan, Pakistan and Iraq a comfy couch, a big TV, a satellite dish and an unlimited supply of donuts.
This would probably have saved them about $4.5 trillion and been a hell of a lot more effective. Fat people with big TVs rarely want to go off and fight somewhere which is going to be less comfortable than their plush leather couch with the built-in cup holder and the recliner thingy.
Everyone would look upon the US in a far more kind way and any potential terrorists would all surely be too busy watching Baywatch re-runs to go and behead anyone. They might even decide that women not dressing head to toe in black is a good thing.