I've looked into some questions here where the "best" programming books are listed and then thought why there isn't a question concerning speeches yet. I think that speeches or presentations from developers or even creators of programming languages which were or are heavily used at some point are particulary interesting.
One of my favorite speeches was recommended to me by someone here on SO: The future of C# I also like Guido van Rossum's speeches but he sometimes seems pretty nervous. Another in my opinion good presentation would be the Google tech talk about Go.
- Which (recorded) programming presentations/speeches are worth watching?
edit: Made this a community wiki as the answer would probably be a pretty long list.