I think Oldboy, Sympathy for Mr. Vengence, and Chan-wook Park's contribution to Three...Extremes are the only Korean fims that I've seen. I'm sure they can't all be as good as those, but they do make me want to see more.
Lady Vengence, J.S.A., and Memories of Murder are on my Netflix queue at the moment. When I heard about Memories of Murder, I also heard a review of another film that sounded interesting: The President's Last Bang.
On the other end of the spectrum is the North Korean film Pulgasari. Has anybody seen it? It seems to me that a film about the making of this film would be much better, but I would still kinda like to see it. A couple of years ago, Duke University had a film festival of movies from "Axis of Evil" countries (plus Syria, I think), and they showed this one, but unfortunately I couldn't go.