A few months back, a friend of mine posted an entry on his blog titled "When Did Reagan Stop Sucking." The post noted the sainthood of Reagan after he died, and my friend wondered when Reagan went from a bad president to a good one.
I replied to his post that the post-administration apotheosis will happen to GWB, too, and that some day his face will end up on a quarter.
It looks like the revisionist history is already happening. Prospect magazine has just published an article about GW called "A Truman for our Times."