What was the last really GOOD documentary you've seen?

[Heidi]

54. "Southern Comfort" (2001)

Full documentary:

Synopsis from Rotten Tomatoes:
Kate Davis' digitally shot documentary chronicles the last year in the life of Robert Eads, a female-to-male transsexual dying of terminal ovarian cancer in the backwoods of rural Georgia. Broken up into seasons, the feature introduces viewers to a community of transsexual persons (many of whom have received poor medical care), including Maxwell, Robert's best friend and sparring partner, and Lola Cola, a male-to-female transsexual who has become Robert's life partner after a lengthy friendship. Often regarded as the patriarch of this small but tight clan, Robert finds that his cancer is accelerating; his loved ones all lend support, including his son, his parents, and his beloved granddaughter. When Robert can no longer care for himself, Lola decides to care for him full-time. The two prepare for the annual Southern Comfort conference, a yearly event created for transgendered individuals, where Robert and Lola have been selected to lead a panel, all while Robert's health is in jeopardy. Robert's final wish is granted when he is able to attend the event, joined by his nearest and dearest friends and Lola, his devoted lover.
http://www.rottentomatoes.com/m/1104978-southern_comfort/