I adore documentaries, but especially ones that are gorgeous to watch. I suppose that's why I like Ken Burns "The National Parks: America's Best Idea".
I recently discovered that Netflix has TED Talks on demand, and I saw this amazing one (through the Wii onto my TV) called "Louie Schwartzberg: The hidden beauty of pollination":
Honestly, it's much better through Netflix (search for "Beasts, Bugs & Bio-wilderment"). The quality online just isn't as good, but it's pretty close.
My favorite parts are the bat with the clutching pup and the huge gathering of monarch butterflies. So wonderful! Louie Schwartzberg is a genius!