Two other films:
While John Carpenter's Prince of Darkness may be his most out-and-out suspenseful (at least at this pont of his career), In the Mouth of Madness is arguably his most unsettling, mainly because it has a taste--a hint--of real insanity in it. Sam Neil isn't as engaging in it as I'd like--not his fault, I suspect, he's usually interesting to watch--but the narrative makes interesting loop-de-loops with itself, and causes the hero to end up in what you might call a 'metaphysical moment,' laughing at himself in a moment of black despair.
Rasen was the other sequel to Nakata's Ringu--it basically took up the novel by Koji Suzuki and reconciled the novel's storlyine with the changes Nakata made (in the novel there was no videotape or TV set involved). It was made with Ringu's cast but not director, and was a flop, causing the producers to call back Nakata to make Ringu 2, (the story of which had nothing to do with Suzuki's novel).
The story seems all over the place, as it makes hash of the rules set up by the first film. Then it all comes together and shows us Suzuki's entire vision, not of Sadako taking simple revenge, but of her plan to conquer the world (the title is a clever reflection of the film's plot: where Ringu (or 'Ring') suggests that Sadako's vengeance will go round and round in circles, limited by the actual handover of the videotape, Rasen, meaning 'spiral,' suggests that Sadako has found the means to break out of the circle).
It's an odd trade: in place of Nakata's trademark sense of creeping dread and slowly mounting tension, you have instead a science-fiction drama (I'd like to say 'science fiction thriller' since this is what the story seems to want to be, or is structured to be, only there are precious few thrills here) with a touch of Faust involved. The chills are there, but subtler, more moral and philosophical.