If you have not read “Cognitive Biases Potentially Affecting Judgment of Global Risks” and “Artificial Intelligence as a Positive and Negative Factor in Global Risk“, I recommend reading them. They are excellent book chapters from SIAI Research Fellow Eliezer Yudkowsky, forthcoming in the edited volume Global Catastrophic Risks from Oxford University Press (Nick Bostrom and Milan Cirkovic eds.). If you do not have time to read both, I recommend reading the conclusion of the first, repeated below, and reading the second in its entirety.
Via the SIAI blog.