Actually, if you like 'Ring', then perhaps you should check out 'Audition' (twisted and evil, heh), and also 'Battle Royale' , not a horror film, but it did influence Tarantino and stars Chiaki Kuriyama, (who plays 'Go Go' in Kill Bill).
This site will tell you a bit about them, you'd probably have cheaper alternatives for the US I should think, (should you wish to buy them at some point).
Japan's been doing some great films these past few years.
I've managed to pick up a few fantastic Japanese flicks on my recent trip to the states, the wealth of titles on display is far superior than anywhere in britain.
I bought the Seven Samurai, a fantastic film containing performances and cinematography that transcend the period in which it was made.
I also came across a copy of Battle Royale 2 which, while not as engrossing or thought-provoking as the first, still comes across as a decent flick. (probably due to the death of the original director occuring in the early stages of the film)
Kas, if you're edging into Japanese cinema somewhat, I recommend picking up anything by Takeshi Kitano or Miike Takashi. They make exceptional Yakuza flicks as well as other assorted gems in filmmaking.
