A few of mine —
A Grin Without a Cat [Chris Marker, 1977] The Battle of Chile [Patricio Guzmán, 1979] Harlan County U.S.A. [Barbara Kopple, 1976] Lucia [Humberto Solás, 1968] Attica [Cinda Firestone, 1974] La Commune (Paris, 1871) [Peter Watkins, 2000]
Soy Cuba (1964) is.. the best propaganda film of all time.
I've been meaning to watch Lucia, The Battle of Chile and La Commune but I have a hard time watching stuff that is not available in HD, I suck.
Lucia is going to be released by Criterion soon and I found La Commune in HD on VOD the other day, so I guess I have no excuses anymore.