When it comes to well formulated talks about free software, none seems to beat those from Stallman's lawyer, Eben Moglen. He knows very well how to speak to a crowd, and tends to use local references and languages to explain concepts (professor of law and history of law). Stallman has excellent skills in seeing problems in software before they get noticed by everyone else, but when I want to introduce someone to the philosophy of free software I would rather put on a talk like Freedom of Thought Requires Free Media from 2012 or the now 11 year old talk Die Gedanken Sind Frei from 2004.

1: https://www.youtube.com/watch?v=sKOk4Y4inVY

2: http://www.archive.org/download/3_do_t1_11h_3-Moglen_a/3_do_...