Cat People (1942)
A bit slow, not very horror-like, but a decent film for a rainy day.
Curse of the Cat People (1944)
Entertaining though it has very little to do with it's predecessor. Less horror-like than Cat People, but, IMHO, more interesting.
Ghost Busters (1984)
Great film. If you haven't seen it, you're missing out on a hell of a lot.
Ghostbusters II (1989)
A rare instance where I like the sequel as much as the original.
Not my type.