This is far and away the best conference I have attended.
It is also extremely convenient as it is a block away from my office. Last year I was attending OSCON as an Open Source ESB vendor. This year, I'm attending as the leader of a team dedicated to Open Source Software within Liberty Mutual, Agency Markets (large insurance company) - who knew!?
I typically just go to the sessions, but this year I am going to Businesses Partnering with Open Source Communities: Opportunities, Perils, and Pitfalls and O'Reilly Radar: The Executive Briefing
And of course some cool parties ;)
Let me know if you will be in town and I'll buy you a coffee or a cold one.