Boris Karoff as Frankenstein, I saw it the for the first time when I was about seven. Those stupid flying monkeys in the Wizard of OZ, to this day I still shiver when see those things. The all time scary movie for at least the first third of so of the movie has be THEM!. It's really scary until the ants make their appearence. Allowing for the budget and the Special Effects technology of the 50's though they ain't too bad. Another scary movie, one of the few horror movies that really scared me as I go older, was the British film, Legend of Hell House, I think it was the title. No gore and very little blood, but the suspense will kill you. The movie Alien, the first video tape that I ever bought back in the early days of VHS-Betamax wars, has to be scariest SF film that I have ever since.