The Dark Knight VS Batman '89
It's no contest, The Dark Knight completely annillates Batman '89 in all categories: the writing, directing and acting (especially Christian Bale's Bruce Wayne/Batman and Heath Ledger's The Joker) are all far superior.
The only thing Batman '89 has that comes close to the greatness of The Dark Knight is the music. Danny Elfman's excellent score is on par with Hans Zimmer's outstanding compositions.
Batman '89 is more of a children's movie, it's a great introductory film for really young Batman fans but The Dark Knight is more of a adult's movie, it's for very mature Batman fans.
Batman '89 is a fun movie for the kids but The Dark Knight is a masterpiece made for the grown ups.