Containment (2015) - Residents of a Southampton apartment block wake up to discover that they are sealed inside their building. They must work together to find out why before they start to turn on one another. More of a psychological thriller than a horror and pretty decent too for a low budget British film.
Don't Look Now (1973) - the movie version of Daphne du Maurier's short story of the same name. Again, not really a horror but enjoyable. At least this one sticks with the story line in the book, unlike The Birds. The movie version of that is almost nothing like the book, perhaps made for better viewing though.