I've never really been a fan of pre-70s movies (except maybe the Bonds and one or two Hitchcocks) but I thought I'd give some a punt.
Cat People (40s) Boring. Stick with the 80s version.
The Last Man on Earth (early 60s). Not bad actually, the original adaptation of the story later remade by Charlton Heston (The Omega Man) and most recently Will Smith (I Am Legend). Vincent Price is the last man alive when a plague sweeps the world and leaves nothing left alive but vampires. Slow and dated, to be sure, but quite atmospheric and spooky, with a good performance by Price. Interesting that the "vampires" seem more like the lumbering zombies "invented" by Romero a few years later.
Creature from the Black Lagoon (54). Oh dear. Oh.... dear.

Perhaps pre-60s is a step too far.

I have got a couple of 60s Hammers off YT, though.