I saw the American remake before seeing the original Ringu, and I must confess that I also like the American version more. It seems, however, that those who saw the Japanese film first enjoyed it more. If you like the premise of the story, however, I strongly urge you to read the original novel "Ring" by Koji Suzuki, on which the movie Ringu was based. It's the first novel in a trilogy, I think -- at the time I read "Ring", the rest of the series wasn't available in an English translation, but that may have changed now so I should look it up again. I also have a box set of the original Japanese Ring movies (Ringu, Rasen, Ringu 2, and Ringu 0) still sitting in my drawer unwatched -- I should really get to that soon. (Maybe I'll have an idea for an edit! Who knows, hehe.)

I haven't seen any of the Japanese sequels, but I must say that the American Ring 2 was a travesty (though it was directed by the director of the original Japanse Ring -- what was he thinking?). The only thrill I got out of it was seeing Samara crawl out of the well in a manner that reminded me of Gollum in the LOTR movies.