Scary movies generally suck. I don't find lots of blood, shock value, or monsters scary at all. It's lame. If you want a movie to be scary try making it creepy. Some games are good at this. The original Quake on PC and Fatal Frame are excellant examples.

I was in third fourth grade when IT first came out on TV and it scared the heck outta me. Then in sixth grade I read the book and had trouble falling asleep at night because I was afraid.