City of the Living Dead (1980)

Directed by Lucio Fulci

One of the best known directors of Italian horror films, Lucio Fulci's signature is over-the-top scenes of all out gore.  This film manages to deliver a bit more substance than that with an incredible dense helping of spooky atmosphere.  The name of the movie (probably intentionally) makes it sound like some sort of Dawn of The Dead spin-off (or rip-off).  This is fairly misleading though and the mismatched expectations are probably the cause of it's somewhat underrated status.  Although it was released on videotape under the name Gates of Hell, which makes quite a bit more sense.  Because you see, this is a supernatural horror tale involving demonic possession and strange unexplained happenings.  No real zombies in a John Romero sense.  It proceeds in the end into something in the manner of an adventurous quest.  Also has a fantastic soundtrack by Fabio Frizzi.