Village of the Damned is a 1960 science fiction/horror film starring George Sanders (and that's enough to recommend it) and Barbara Shelley (another plus). It's based on the book The Midwich Cuckoos by John Wyndham. Creepy and very well done. A classic.
Moria calls it "intelligent and thematically audacious". 1000 Misspent Hours says, "it’s probably the best non-Hammer British sci-fi or horror film of the 1960’s". Rotten Tomatoes gives it 95%.