I find it increasingly hard to resist the notion that he is the most enduring director of our time. I've now seen Syndromes and a Century (the best place to start), Blissfully Yours, and Tropical Malady and wish to rewatch them all. Uncle Boonmee Who Can Recall His Past Lives (not yet on DVD) won the Golden Palm at Cannes this year. Themes of his movies include dreams, medicine and its authority relationships, sex and eroticism, homosexuality, the nature of cinema itself, memory, sudden fractures of reality, surrealism, and the modernization of Thailand. [Insert Dancing About Architecture cliche here.] You could frame most of the shots from these movies and turn them into stunning photographs. The plot structure is stronger than it appears at first. These movies also have notable (though quiet) soundscapes, as you would find in a Tarkovsky film.
If you expect to disagree, try then the excellent Ong Bak.