What a great thread.
I concur with the poster who recommended "The Devil and Daniel Johnson"
Two very good documentaries that I haven't seen mentioned yet are;
"Man on wire"
The story of Philippe Petit's illegal attempt to tightrope walk between the Twin Towers in 1974. Although the only media of the event were still photos it made my hair stand-up when it came to the moment of truth.(very impressive considering my baldness)
http://www.imdb.com/title/tt1155592/
"Hippie Masala"
A light documentary about 4 different people who were among the throngs of people making the pilgrimage to India in the 60s and 70s seeking spiritual enlightenment. The difference with these 4 is that unlike most, they stayed.
http://www.imdb.com/title/tt1131674/