Definitely Japanese monster movies, especially Godzilla and Gamera. They're the greatest.
The Danish monster film
Reptilicus (Saga Studios; 1961) is my favorite non-Japanese monster film.
I also love many of Ray Harryhausen's films, including my favorite,
The Beast from 20,000 Fathoms (Warner; 1953)! The British film
Gorgo (King Bros./MGM; 1961) is really good, too! And there's also
The Blob (Fairview/Paramount; 1958), which used to really scare me as a kid, and
Dinosaurus! (Fairview/Universal; 1960), both directed by the late Irvin S. Yeaworth, Jr.
There's a lot more I can go into, but it's late, and I'm tired right now.
