Quick note: I'll be at Shmoocon this year, had my ticket for a few months. I'm sure I'll be tweet-commenting on every talk. The popularity of twitter should be entertaining, they appear to have an official twitter account which I hope will be used well during the event.
There's no single talk that stands out this year. I'm glad that the typical talks are gone; the only repeat speaker I recognize from last year is Charlie Miller. This is a good thing; as much as I love johnny or kaminksy, the freshness will be nice.
Watch out for lots of geeks with tweets.