Marebito - A mysterious and vengeful spirit marks and pursues anybody who dares enter the house in which it resides.
One Missed Call (Chakushin Ari) (2003) - Legendary filmmaker Takashi Miike doesn't disappoint. Gripping stuff, very creepy, and unlike most Asian horror, the climax is scarier than the rest of the movie.
악마를 보았다/I Saw The Devil (2010); South Korean horror/thriller...so terrifying yet brilliant performances!
Someone Behind You - another atmospheric if somewhat confusing Korean horror.