The 'Planet Earth' stuff on blu-ray is always stunning.

I'm a big F1 fan so I thought 'Senna' was excellent too.

Ah, how could I forget Planet Earth, especially on Blu Ray is an experience.. My buddy and I in our college days used to watch it while uhm.. smoking up some of that "earth". Really enhances the experience hehe..

Not all documentaries are created equal. Zeitgeist is propaganda and conspiracy theories, edited together.

There are a lot of great documentaries out there, though, which follow real people and focus on finding the truth in some form.

I'd highly recommend Hoop Dreams, Grizzly Man, and The Last Waltz.

You have great taste!

Some for you to look into :

Ecstasy of Order : The Tetris Masters (people who compete in the old-school unforgiving NES Tetris)

The Smartest Guys in the Room (incredible story of how Enron screwed people, and the dangers of deregulation leading to gangster-like elite private control of utilities)

The Fog of War (a total masterpiece by the great Errol Morris, interviewing an elderly and deadly honest Robert S McNamara about the cold war, Vietnam, etc. it's electrifying, and I went into watching this thinking poorly of RSM, but came out incredibly moved by his honesty and reflections)

There are more, but those pop to mind for me :0 Good list!

Ancient Aliens

Man on Wire

Most recently I really enjoyed The untold history of the United States by Oliver Stone. It links a lot of events together from WW1 to Obama.

For artistic documentaries, Baraka and Samsara are amazing on blu-ray.

For nature, Planet earth ofcourse, also Africa and Frozen planet are absolute must haves from BBC Earth series and Human planet is great as well. Try to get the versions with David Attenborough narrating. I pretty much have the whole BBC earth series on blu-ray, fantastic series. Planet Earth 2 might be my first UHD purchase, although I might hold off until I have a 4K tv. (The new series should be out in March)

I also enjoy documentaries about the universe, any really, Cosmos: A spacetime odyssey comes to mind. Most recently Discovery had the documentary about the Rosetta mission, great stuff.

For guilty pleasure, Mayday series. Last time, 1 missing washer made a 737 go up in flames right after landing. Lose bolt in the flaps punctured the fuel tank after a botched repair job.

I have a currently incomplete list:

The Red Bomb
Messengers from Moscow
Red Empire
WW2 The Complete History
Liberators-The Soldiers of the Red Army
Last of the Czars
The Russian-German War (the one with the skull)
War of the Century
Secrets of War series
Secrets of World War II
Nat Geo's Hitler's Last Year
Defending Berlin - The Last Battles
WWII The Battle of Berlin Death of a City
The Conquerors: Marshal Zhukov
The Great Commanders - Georgy Zhukov
Secret History of the Third Reich: The New Order (1991)
Defending Berlin
WW2: The Waffen SS
The Enigma of the Swastika
Line of Fire Stalingrad
Stalin in Colour (Smithsonian Channel)
Good Morning Mr Hitler
The Great Battle on the Volga (Stalingrad)
History File The Soviets
Scorched Earth
Hell's Battlefield
The Battle of Stalingrad (three-parter): The Assault, The Pocket, The End
Clash of Warriors Paulus v Chuikov (and others in the same series)
The Occult History of the Third Reich
Hitler's War: The Eastern Front
Vietnam: The Ten Thousand Day War
Battlefield Vietnam
Russia's War: Blood Upon the Snow