Good call on Koyaanisqatsi and Boogie Nights, Taw.
I've been trying to catch some of Kurosawa's stuff, in particular Ran, Rashomon, or Shichinin no Samurai (7 Samurai), but to obtain it legally would require far too much money seeing as it's being packaged for film buffs with lots of money and not a lowly student. They weren't readily available last time I had a look through the less than legal channels either.
Little bit surprised by Eraserhead there, it's not exactly something I "enjoyed" watching but it was good fun just trying to make sense of some of the imagery and have conversations with my friends about it afterwards. (The ideas brought forth are pretty weird!)
Downfall (Der Untergang) was incredible, I watched it the other night. The actor who played Hitler was incredible. Apparently he spent some time listening to recordings of Hitler at some sort of dinner party in Finland to accurately imitate his conversational stylings. The killing of Goebbels' children in particular sent chills down my spine.
Also noticed a lot of Hayao Miyazaki films in the list, I saw Spirited Away in the cinema a few years ago and it reminded me of a lot of the weird fantasy movies and cartoons I enjoyed as a small child that really stretched the imagination.
Forgot to mention City of God in my last list, that was an excellent movie. As well as, Shawshank Redemption, Cold Mountain, Memento, American History X, The Pianist, Rushmore, Trainspotting and Family Guy: The Movie
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Currently I'm trying to get hold of the original War and Peace filmed in Russia in the 1960s which apparently most closely follows the book itself. (I'm finally reaching the end of that enormous book!) I've seen some clips from it and the Battle of Borodino in particular looks nothing short of incredible with what must be tens of thousands of extras involved. Apparently after adjusting inflation over the years it's the most expensive film ever made.