Winged Migration
The Sorrow and the Pity
One Day in September
The Last Days
Scared Straight!
On Any Sunday

Hoop Dreams
Brother's Keeper
End of the Century: Story of the Ramones
Dogtown and Z-Boys
Stevie (also directed by Steve James of Hoop Dreams)

American Movie
Brother's Keeper
Paradise Lost
Grizzly Man
Grey Gardens

1. Dogtown and Z-Boys
2. Hoop Dreams
3. Paradise Lost
4. Murder on a Sunday Morning
5. Murderball

1. Metallica's "Some Kind of Monster"(how could this one not have been mentioned??)
2. "Hoop Dreams"

and I'd throw in 3."Empire of Dreams" . i know it isn't a standalone, but it's awesome!

4. "Bowling For Columbine"

5. ? I don't see that many docus.

Z Channel: Magnificent Obsession
Mayor of Sunset Strip
American Movie

These 3 alone are must sees for anyone who claims to love movies and all things Hollywood

......

Jupiters Wife
The Weather Underground

The best 2 documentaries NOT on dvd:

1- Hearts of Darkness (the doc about the making of Apocalypse Now)
2- the recently aired AMC documentary on Dazed and Confused

I second this recommendation

other docus:

- Double Dare (female stunt women)
- Bus 174 (totally rivetting)
- My Architect
- Burden of Dreams

when and if this get released on DVD:
- Midnight Movies: From Hollywood to the Mainstream.

It took a while for someone to even mention the best documentary of all time.

HOOP DREAMS

My Flesh and Blood
Celluloid Closet
The Times of Harvey Milk
Fahrenheit 9/11
In Memoriam - New York City, 9/11/01

Paradise Lost (and sequel)
My Flesh and Blood
Grizzly Man
Murderball
Bus 174

Heroin Town
Brothers Keeper
American Movie
Dark Days
Keep The River On Your Right: A Modern Cannibal Tale

Thank God someone finally mentioned Grizzly Man, which I feel was the best documentary of 2005 (that I saw).

If you like Herzog's documentaries (nobody has mentioned Kinski: My Best Fiend yet - it's certainly in my top 5 docs of all time, as well as Lessons of Darkness, about the first Gulf War), you should certainly check out this offering, from Werner Herzog Film. I just ordered the set. It has over 20 of his documentaries on it, plus a couple features. It's Region 0 NTSC, even though you have to pay in Euros.

Z Channel=Strong agreement.

The Civil War
The Seven Up Series
Hoop Dreams
The Kid Stays in the Picture
Olympia

I'd also like to mention a few more good ones of fairly recent vintage: Buena Vista Social Club, Standing in the Shadows of Motown, The Wonderful, Horrible Life of Leni Riefenstahl, and Born into Brothels.

A lot of good ones have been mentioned in this thread. I'm going to have to seek out the ones I haven't seen.

1. The Life of Birds (David Attenborough has never done anything bad)

2. 7 Up

3. Grey Gardens (bet they felt like they were filming a train wreck)

4. Crumb

5. Trinity and Beyond:The Atomic Bomb Movie (this is probably my fave)

and Race to the Moon from the History Channel. I've watched that one over and over.

If you're interested in historically important documentaries -- or just like old documentaries -- you should also look at:

In the Land of the War Canoes (pre-dates Nanook of the North)
Grass (one of my favorite silent movies and still quite impressive)

Meeting People is Easy: A Film about Radiohead
Capturing the Friedmans
Crumb

those are my favorites

also, I Am Trying to Break Your Heart is a very good documentary

Cosmos
The Planets
The Corporation
Grizzly Man
The Endurance

I'll have to think about five, but I don't think The Thin Blue Line or The Wild Parrots of Telegraph Hill have been mentioned. Both are excellent. The Thin Blue Line really shook me up both times I saw it.

No particular order:
Roger and ME
Thin Blue Line (anything Morris )
Hoop Dreams
American Movie
Harlan County, U.S.A. Coming Soon


Not on Dvd:
The Emperor's Naked Army Marches On
Early Wiseman
Hearts of Darkness: A Filmmaker's Apocalypse

I can't name 5, but Hoop Dreams is all I care about.

Actually, I like Startup.com a lot too.

I saw "Enron: The Smartest Guys in the Room" at a film festival last year. Its coming out on DVD 1/17/06. Very well done.

1. The Rise & Fall of ECW
2. Michael Jordan Ultimate Collection
3. Super Size Me
4. Bret Hart: The Best There Is, There Was, There Ever Will Be
5. March of the Penguins

Oh, wow! You've got to be a hard-core Radiohead fan to even "get" what's going on in this one. But it's definitely one of the most unique and creative band documentaries I've ever seen.