Eliezer Yudkowsky and Scott Aaronson talk Technological Singularity and Many Worlds (from summer 2009). Peculiarly, given the trend of the conversation, it’s aged well.
The Paperclip Maximizer is on its way to becoming the most significant bad argument in existence. EY’s high-intensity rants about how thoroughly one-world theories are busted, however, are truly awesome. You have to hang on to the end to reach Dr Evil (but it’s worth it).