Marebito, Reincarnation, Rasen, Rampo Noir, Suicide Club, Infection...to name a few.
I found all of these very 'worth watching'.

i love j-horror but i hate when they make it into american films
Chad i have whach all of those moves and YES they are worth watching
suicede club realy toch me is true you dont have to be alive to have a conection with the peple you love

but...
 

isn't that most? Just kidding, but seriously. :confused:

i think its ring-gu but im not sure

Audition
Audition (film) - Wikipedia, the free encyclopedia

Dark Water
Dark Water (2002 film) - Wikipedia, the free encyclopedia

As previously mentioned, One Missed Call
One Missed Call (2004 film) - Wikipedia, the free encyclopedia
(Anyone notice a lot of the really creepy horror films involve technology and ghosts?)

And then there's this really wierd one, Naked Blood
Naked Blood - Wikipedia, the free encyclopedia

Edit:
I know they're not Japanese (Korean!), but the works of Mr. Chan-wook, the Vengeance Triology (Sympathy for Mr. Vengeance, Old Boy, Lady Vengeance) are something that needs to be watched.

never seen one ..

I'm embarrased to admit, Horror movies have a long-lasting effect on me.
I usually try to avoid watching them.

Here, in America, they play 'The Grudge'...
Which, I have to say, is enough to scare the 糞 (is this the correct Kanji?) out of me.
I have a very vivid imagination.

If there's one thing that would ruin your trip to Japan, it would be to have ghosts follow you around everywhere, when no one else can see them but you... And there's virtually nowhere they won't appear...

(X_X)

Seriously? I don't find The Grudge incredibly scary myself.

Omg, if you want to see a scary american movie....you need to watch Silent Hill. That movie is so freaky, me and a friend had to stop wathcing it and watch something else in order to sleep. We stopped at a bathroom scene and we were terrified to go in the bathroom [and we had to really go lol]

Yea But Most People Wont Get, Silent Hill,

What Its Really About Unless The [Passed] The Game