Gummo
Will blow your mind. To this day...I am still blown away by the pure insanity and realism.

Eraserhead
a trip on acid without doing acid. But not recomended for those with short attention span.

Most Clint Eastwood films....I enjoy too.

[edit] I am also a huge sci-fi fan....Alien series is my fav.

I HATE "chick flicks"