Now, after watching several of his movies and hearing him talk a bit I have to say that while I don't like his approach to some things (some of the "stunts" in his movies just feel too calculated and a bit stupid/pointless) I do have to give him credit for being a genuinely funny guy with an interesting take on issues that a lot of people don't want to talk about (or even think about in many cases).
I still think he dropped the ball big time on Bowling for Columbine. I think I've mentioned it before, but I didn't like how he focused exclusively on Canada and the US while completely ignoring Mexico which has extremely draconian anti-gun laws and yet has a major gun problem. Looking at some of his other work, I can't help but think that if he had just looked at the the three countries and their economies and if he had factored in social effects that extreme poverty and poor education have on people, he could have come up with a really useful commentary on the gun problem (or more precisely the violence problem) in the US/world.
That aside, the other stuff I've seen him do is really fascinating and I think he asks some really significant questions in all of his movies. I don't always agree with the conclusions that he comes up with, but he definitely has a nicely twisted sense of humor when it comes to how he gets his point across. He's certainly given me quite a bit to think about.
If you haven't caught The Big One, I would recommend checking it out (it was on IFC tonight). It's kind of fun and it doesn't leave you with the same sense of disgust that F9/11 does. He still does some serious finger pointing but he does it with more of a sense of humor and with a bit less outright sarcasm. I also liked his style of cutting between his book tour and his attempts to talk to CEOs. On the whole this movie was still thought provoking but it was also more entertaining and fun to watch.