I'm not a big horror movie fan. But when I was in college, I saw Night of the Living Dead during a dorm Halloween movie night, and I was pretty impressed. Actually my first reaction on seeing it was that I was glad I hadn't seen it when I was younger, because the whole zombies-breaking-into-a-house motif would have scared the wits out of me. I mean, I was terrified of that premise even without having seen the movie, just having heard about it as a kid.
Anyway, what I thought was really interesting about the movie was that it seemed to offer a subtle challenge to the prevailing order of racial oppression and disdain in 1960s America. The smartest, most level-headed character was a black man, and after weathering the storm of the zombie attack, he is anticlimactically shot down by a police helicopter that thinks he himself is a zombie. An ambiguous but very thought-provoking set of images.
I had long wondered if anyone else shared my reading, until recently when I came across this article that advances and develops a much more detailed and thought-out version of my interpretation.