Charlie Stross has put some scary reflections on the real cost of the Iraq War on his blog. So far the direct cost to the USA is more than $500 billion (with the indirect cost to the global economy perhaps as high as $3 trillion). Charlie points out for the amount of money the USA has spent they could have had a fully funded manned mission to Mars Alternatively, the USA could have used the money to more than meet the Kyoto Protocols. He concludes by asking, ‘And what isn't going to happen now, because we pissed it all away on the desert sands?’
One answer to his question: It costs about $5 per person to provide basic water purification facilities. About 1.1 billion people currently have no access to clean drinking water. For about 1% of the money so far spent on the war, the USA could have met their need for clean water (thus saving the lives of about 30,000 people per week).
Update: Cosmic Variance has a short post on the amount of money lost/embezzled in the course of reconstruction efforts in Iraq. Apparently the figure currently stands at about $14.9 billion (or nearly three times the annual budget of NASA).