There used to be a blog associated with the Skeptic Society called Skepticblog. It is archived here. They had a lot of posts on climate, mostly by paleontologist Donald Prothero. Most regular commenters there tended to tow the standard AGW line, along with Prothero. There was a very articulate commenter, with the handle markx, who just seemed to run circles around them. He didn't deny any basic AGW theory. He just challenged a lot of points and was very effective. On this post, I noticed one of my comments appearing in an odd place and that markx was getting mad and leaving. When I figured out what was happening, I started a discussion in the comment policy thread here. You can go to those two links and read the whole thing.
List of Links