Ask HN: Favorite Dev Conference Talk Videos?

What are the best conference talk videos that you have seen? Which have you learned the most from? Here are a few of my favorites.

[1] Paul Irish - Fluent 2012: Paul Irish, "Javascript Development Workflow of 2013"

http://www.youtube.com/watch?v=f7AU2Ozu8eo

[2] Sandi Metz - SOLID Object-Oriented Design

http://www.confreaks.com/videos/240-goruco2009-solid-object-oriented-design

[3] Lea Verou - More CSS secrets: Another 10 things you may not know about CSS

http://vimeo.com/52882799