1. War of The Worlds  - "As Earth is invaded by alien tripod fighting machines, one family fights for survival."
Now, obviously this movie isn't scary. But it has aliens. And aliens are cool. So, get over it. Plus, this is one of my favourite movies. Ever. Top 5.
2. Casper  - "A paranormal expert and his daughter bunk in an abandoned house populated by 3 mischievous ghosts and one friendly one."