The most exciting thriller to come out of Hong Kong in years also has the cheesiest title -- "Infernal Affairs" -- (the Chinese title is "Mo-Gaan-Do," which is the lowest canto of hell in Buddhism).  But don't let the title put you off.  This is a taut, muscular and thoroughly enjoyable movie that's several notches above the usual crime drama genre.  Check out this review if you want more information on the movie:  http://www.rottentomatoes.com/click/movie-10002335/reviews.php?critic=all&sortby=default&page=1&rid=843342

The Asian import DVD release features DTS sound and, bar none, is the best sounding DVD I have ever heard.  Highly recommended.