I saw this in the theater when it first came out. It stuck to me like glue. I was creeped out for days. Then, I watched it with a friend the other night and was struck, once again, by just how effective this movie really is.
A true-crime writer, played by Ethan Hawke, moves his family into the home of the family whose brutal murder he is researching. He finds a box of 8mm movies in the attic that may reveal that the murder he is investigating is one of many by a serial killer. He makes bad decision after bad decision all in hopes of another best seller, breaking another big case. Weird and terrifying things start to happen to him and his family, who have no idea what is going on. He eventually redeems himself by fleeing into the night with his family but that doesn't solve their problem the way he hoped it would.
Maybe it was Ethan Hawke, who I may still have a soft spot for after all these years. He's a good actor and he throws himself into the role completely. Or maybe it was those creepy as fuck home movies. The movie is expertly crafted, relying on light and sound far more than CGI.
Its not a perfect movie though. There is some CG silliness. The very end is sort of dumb. But still, its leaps and bounds better than most of the horror that's coming out these days.
Surviving Horror Protip: Don't move into houses where brutal mass murders took place. Just don't.