I was lucky enough to catch a Hou Hsiao-Hsien retrospective about a month ago and I haven't been thinking about many other movies since.  I won't even pretend to have seen enough movies to decide on the best living director, but as far as the 90's are concerned, I don't think there are many bodies of work (outside of Kiarostami's, possibly) that can even begin to approach what Hou Hsiao-Hsien has done this past decade.  His movies have stuck in my consciousness like nothing else has in a very long time.