http://en.wikipedia.org/wiki/List_of_cognitive_biases
http://en.wikipedia.org/wiki/List_of_common_misconceptions
http://en.wikipedia.org/wiki/List_of_fallacies
http://en.wikipedia.org/wiki/List_of_memory_biases
I know the trend here is against simple links as top-level posts, but I think these links are powerful enough to stand on their own. I would be very surprised if most people here have already read all of these links. Also, it seems like a good sign that this somehow got modded up to 1 while sitting in my drafts folder.
Thanks to Lone Gunman for the links.
It's great to get in the habit of knowing these biases and looking for them.
One important point is to beware of the meta-bias (actually an instance of confirmation bias): it's all too easy to use biases to knock down an argument that you're already against, and ignore the biases in your own reasoning.