Now I'm not a big fan of reading movies (subtitles), but this one is pretty good. It's a Korean film that follows the "dead girl ghost with long hair" theme that has been running rampant in Asian cinema.
The story line follows 2 young sisters as they clash with their new stepmother. Weird things start happening as they hint to the older sister's psychiatric issues.
This is as much of a thinker as it is a scary story. Watching it twice will actually help you undersand things better, and picking up on those things is reward enough to watch it twice. It is the highest grossing Korean horror film ever and the first to be screend in American theatres. The recent "The Uninvited" is a bastardized American remake and doesn't hold a candle to the original.
Here is the wiki, it is filled with spoilers so don't read it if you want the movie to surprise you:
http://en.wikipedia.org/wiki/A_Tale_of_Two_Sisters