I'm normally not the person to ask for film recommendations. Either the films I like are obscenely popular already (Nolan's Batman films) or kinda...well...obscure (Mr. Sardonicus). But you guys HAVE to seek out the original version of The Stepfather. Not the remake, not one of the sequels, but the original.
That's some scary goodness right there, man. And the best-worst?-part? It's based on a real-life killer. Lost his job, carried on leaving everyday to set up a new identity, and one day shot his family. Then he disappeared for eighteen years. When they found him, he was married again...and had just lost his job again.
So yeah. Go find that movie. It may take some work-it's a little hard to come by-but it's well worth it. Sweet dreams.