alrighty
Atlantis - Luc Besson directs. Best underwater film ever. Ever. No plot, just the most beautiful cinematography you've ever seen.

The Corporation - Best analysis to date of corporations, the dominant institutions of our time. Noam Chomsky, Michael Moore, Howard Zinn, Naomi Klein and a whole bunch of CEOs (Shell, Goodyear etc)
The Triplets of Bellville - Possibly the best cartoon ever. At this calibre, its not even just animation any more, its art.
The City of God - In the City of God, a slum in Rio di Jenero (sp?), the story of the neighborhoods kids growing up. Gangs, drugs, and the protagonist's quest to survive and makle something better of himself.
edit: I should mention that the last 3 of these are NOT available on Nova. Nope, not there. Don't even bother checking, cause they are most certainly not there.