Chandler Carruth's CPPCon talk [0] this year was also great (surprisingly, as I had a fairly low opinion of most of the others). It wasn't better than Mike Acton's [1], but I suspect that it was more actionable for most devs.
Really interesting to hear how essential it is to have tools that allow manipulation of source code. That's one of the great things about Lisp, in that it's super super easy to write code that manipulates code. Also interesting that gcc was a roadblock in that they didn't want the AST and other useful source code manipulation tools to be freely and easily used without GPL restrictions.
[0] https://www.youtube.com/watch?v=fHNmRkzxHWs
[1] https://www.youtube.com/watch?v=rX0ItVEVjHc