welcome to the forums, noise! don't mind seemingly rude comments like this:
what about the entire Showtime series http://en.wikipedia.org/wiki/Penn_%26_Teller:_Bullshit!]Bullshit?
the episodes are only half hour and they're superliberal but they count as documentaries imo
the word you're looking for is libertarian not liberal and they're awful sensationalist fucks. the latter being the single greatest criterion for making a documentary afaik
documentaries I've seen:
blue vinyl - vinyl is awful but this shit is derivative of Michael Moore's garbage and impossible to watch
louis theroux's law and disorder: philadelphia - ok if you don't mind theroux I guess
eden's lost and found: philadelphia - not sure this qualifies as a documentary and it's kind of bullshit but it's essentially about the environmental-social aspects of urban sustainability so I think it's ok
some other ecological stuff none of you want to see