ETA: I was going to mention this the other day when I found out about it, but the Director's Cut of Dark City was released at the end of July. I highly recommend it. Though the additions/changes are minor, they add a different level to the story that I find even more enjoyable. Plus I suggest you watch the special features. These poor guys went through hell getting this movie out originally. At one point they were actually told by the studio to "dumb it down" because audiences wouldn't get it.
Plus I am just in heaven listening to Alex Proyas talking about the movie in the commentary.