"I hope that you will be understanding when I mention my fifth choice, which is An Inconvenient Truth. Davis Guggenheim justly received the Oscar for his work on that movie. He’s a great friend; I was with him last night. He’s so talented, and he did such a good job in that movie. Of course, I’m hopelessly biased in including that in the list, but I’m encouraged by how many positive comments people made about how it affected them."
Source