Planet of the Vampires (1965)

Technically the monsters in this movie are space-zombies, but this was before Night of the Living Dead so vampires were more marketable. Mario Bava directed this film, and he's primarily known for his atmospheric visuals. Here are a few examples:



It doesn't have a particularly interesting story or characters, but the mood is wonderfully bleak and oppressive in a stylish Italian kind of way. There's also a nice Lovecraftian scene where two Italionauts are trapped in an ancient alien spacecraft. If aliens with heads this big couldn't get out of their situation, what hope do our guys have?