World Trade Center: Anatomy of the Collapse: decent portrayal of what happened. I think the details of the collapse are portrayed slightly differently between this 2002 documentary and more recent analyses. Nothing really new for those of us condemned to follow the 9/11 Conspiracy stuff. Good video of how uninsulated steel structure collapses in a fire.
Bush Family Fortunes: The Best Democracy Money Can Buy: A Greg Palast documentary, I think he overplays his "discoveries" that seem familiar to me. The story is that Bushes aren't to be trusted. I agree, but it's nothing exceptional.
Uncovered: The War on Iraq: This one's a little better. While mostly old news, the interesting part was David Kay's discussion of how he went about reviewing whether WMDs were in Iraq after the war. While Kay was clearly a conservative, he was also clear in setting up an unbiased review process. Kay got the right result, while Bush handed us a disaster.
Murderball: The best of the lot, covering the game of quadraplegic wheelchair rugby, with an unvarnished human element to the documentary. I highly recommend it. If you get this DVD, you must watch the "extra" segment featuring the stars' appearance on the TV show "Jackass," where they show themselves to be male twenty-something jackasses - full of life, humor, and mind-blowing stupidity. And then the contrasting reaction seeing the Iraq war veteran amputees, none of whom look old enough to have graduated from high school.
Before Stonewall: A 1984 documentary on gay rights and culture in America prior to the 1969 Stonewall riots, it felt more like a series of anecdotes than an overview. It provided some context for a period I know nothing about, but someone else needs to give the history another try. It would be interesting to learn about gay rights in other countries during that period too.
The "Grizzly Man" documentary is well known, but I'd encourage people to also watch The Wild Parrots of Telegraph Hill for a perspective on a similar but far less harmful person who can't fit in society and anthropomorphizes his animals.
And while not a documentary at all, I can't ignore the Deadwood television series. It tries to be a cowboy western co-written by William Shakespeare and William Faulkner, and it comes close. Second season isn't quite as good as the first, but it's still one of the best shows I've ever seen. Hard to believe there's better stuff than Joss Whedon's Firefly series, but there is.