Yeah, that's a damn good documentary too.

Out of interest, do any of you HAVE to believe everything in the documentary to find it interesting? I've watched several documentaries that just didn't convince me of the premise but still found them interesting nonetheless.

Zeitgeist and Addendum were two of the most eye opening documentaries I've seen to this day. Never looked at things the same after that, and never quite as trustworthy of authority since. Tough to pick just one but Zeitgeist is definitly up there for me as well. 

Oh man, where do I begin. I'd always been a huge fan in documentaries, even if it's a topic I'm not necessarily interested in.. 

The King of Kong
Food Inc.
Super Size Me
Zeitgeist 1 and 2
The Obama Deception (Yeah Alex Jones is a bit of a loon but he's more subdued and presents some more reasonable information and facts here)
Loose Change: An American Coup 
Requiem for the American Dream
The Corporation
Pretty much anything Michael Jordan related
30 for 30: Catching Hell (as a Cubs fan it hits really close to home)
This Film is not yet Rated
Metal: A Headbanger's Journey
Metal Evolution Series
Metallica: Some Kind of Monster
Uploaded (Napster Documentary)
Roger and Me
The People VS George Lucas
Star Wars: Empire of Dreams
6 days to Air (South Park)
Goin Down to South Park (more mockumentary but still entertaining and informative)

I'm sure there's more but this is just off the top of my head

Zeitgeist is full of lies, almost a test of how blindly someone would believe anything on a documentary, is full of fake data and a clear agenda behind, make some research and prepare to be disappointed.

As for my favourite one, it depends on the genre, overall i would say:

- Cosmos 
- Woodstock
- Searching for Sugar Man
- Planet Earth II
- Heima

One of those.

No. It's still stimulating to consider another point of view. And like any other movie (for example, Tommy Wiseau's The Room) a documentary can also be interesting for reasons the creator didn't intend.

I really liked Montague of Heck. It takes Kurt Cobain the icon and shows him in a more personal, frail and broken light. It really leaves a person with deep empathy for the man... not the legend. He was really just a sad, unwanted human being who couldn't deal with life. Tragic.

Similar to me. I'd not really been interested in the bigger picture until Zeitgeist. You might find this site interesing. I'll certainly be searching out some of your suggestions, so thank you:

http://topdocumentaryfilms.com/

Im a sucker for nature/animal documentaries.

Recently:

- History of the Eagles
- Searching for Sugar Man

and a bunch of German and French nature/architecture documentaries you've never heard of (Wildes Deutschland/Skandinavien/Russland, Paris-Berlin, Alpen von oben, Bauhaus: Modell und Mythos, Baukunst, Giganten der Gotik [a documentary about Cathedrals] etc.)

I really liked Meerkat Manor, a tv series on Animal Planet.
It was a mixture between a soap and a documentary.

Metal: A Headbanger's Journey.
Supersize Me.
Blackfish.
The Death and Resurrection Show.
Cosmos: A Spacetime Journey.