Now, I believe that a lot of skeptics agree that Bill Maher is... let's call it inconsistent... when it comes to his rational beliefs about science and the like. He's an atheist, and in Religulous he repeatedly brings up some of the problems and fallacies of religion. He takes the reasonable position of saying that you CAN'T know about the existence of god -- and most atheists acknowledge this position as well. I don't believe in god, but I also know that I can't prove or disprove his existence; I just see little reason to hold the belief the such a being exists.
Contrast Bill's reasonable stance on the existence of god with his beliefs regarding germ theory and vaccination, and you'll understand why I have mixed feelings about the guy. He tends to jump to conspiracy theories all to readily, but nevertheless I appreciate the fact that he shines a light on other aspects of our society that I also find troubling.