Ask HN: The best conference you attended and why?

I am organizing an event in October called Fundation and I wanted to get some feedback on the important facets of a Venture Capital event.

I have been to a lot of conferences over the past 10 years and have even organized a few, however I wanted to reach out to hear about the best conferences you have ever been too and why?

I'll go first: The best conference I have ever been to was CUTC (Canadian Undergraduate Technology Conference,I believe it has been replaced by www.hiepic.com) the reason is that it had really smooth registration, a perfect balance of both business and technical discussions, demo's and workshops.

Thanks in advance