Shouldn't this be in the Chit Chat section ???
anyways, the definition of scary is different for different persons... some get scared to spooky sounds and atmosphere
, others to creepiness OR painted-faced ghosts OR darkness OR gore/blood etc etc etc.... so it is extremely difficult to figure out the BEST/MOST scaring movie....
Being a horror-movie buff, I can suggest you some good ones to watch if you haven't watched them already....
The Others;
The Sixth Sense;
Session 9;
Gin Gwai (The Eye);
Shutter;
The Tale of Two Sisters [Beautiful and Scary];
Ringu/The Ring;
REC. (hollywood remake is "Quarantine")
One Missed Call [watch the original]
and many others....