Richard Stallman is a very interesting person, I had the pleasure of meeting him in Belgium during Fosdem. The open source scene will remember him as one of their best fighters.
But it´s not only Stallman, look at Miguel de Icaza who works at Gnome. Also a very interesting person you could end up talking for days with these ppl. I whas talking with Miguel and Richard for hours until the Fosdem crew asked them to continue outside because university security wanted to close up the buildings. It´s amazing that these people work so hard for so little pay. With their expereience they could easily work for any major IT company but they had a choice, open source.