A lot of people (judging exclusively by this comment) didn't like Eliezer's talk at the Singularity Summit, but I thought this one was good. I don't think any of it will be new most LW-ers, but it was interesting, and funny, and probably introduced a lot of new ideas to the audience there. The only other talk I've watched so far was the Dan Barker one, which I also thought was good.
Added to post.
We're still missing PZ Myers, and the first speaker (the president of American Atheists, whose name temporarily escapes me). I think that may be all, but I can't be sure since the Skepticon website is down.
The talks from Skepticon IV are being posted to YouTube.
So far we have:
ADDED:
More to come soon, hopefully...