[Sculpt]

Lots of great movies. I would only consider Rear Window a non-horror movie, though that's totally subjective. Obviously a ton of these are sci-fi, but I wouldn't say they aren't horror, unless anyone wants to say The Thing 82 isn't a horror movie.

From your list of films on the borderline...

I think these 4 films stand as colossal great films of the wider horror genre. If I may include all of them at once, these films are full stories, based on books, amazing ideas full of ramifications to life, true classics:

1. The Day the Earth Stood Still
2. The Incredible Shrinking Man
3. The War of the Worlds
4. The Hunchback of Notre Dame

These three are the same types of movies, but the stories/films are not quite as epic:

5. This Island Earth
The Amazing Colossal Man
The Thing from Another World

These 2 are worthy movies, that are famous and unique, but in my opinion, don't have the depth of the above mentioned.

The Beast from 20,000 Fathoms
The Killer Shrews