1. David Fincher. By far the best. So far he has not let me down with any of his movies. Even Alien 3 has some redeeming qualities and I don't blame him because I know of all the studio interference he got when trying to make the film, which he got thrust into very late in the game. But I think all of his movies so far have been top notch and visually brilliant. I really hope he doesn't mess up.
2. Steven Spielberg. If you would have asked me this question when I was growing up, my favorite director would have been him, hands down. But since the late 80s/early 90s, he has stumbled quite a bit. And now I only seem to like less than half of what he puts out. It's only been fairly recently that I've started to like his movies again, like Minority Report and War of the Worlds. But even his more highly acclaimed fare, like Saving Private Ryan and last year's Lincoln, I thought were manipulative and overly saccharine in parts, which completely undermined and ruined any impact the good parts had. But I can't deny how incredible his early movies are, and what effect they had on me growing up and have to this day. Close Encounters and Raiders are my absolute favorite movies, so I can't possibly turn my back on that.
3. Ridley Scott. His movies are generally very solid, and I know I can count on them being visually stunning. His only stumble IMO has been Prometheus, which I thought had some real WTF logic problems. But I place him on my list because of his triple whammy of Alien, Blade Runner, and the often overlooked Legend.
Special mention to Joe Wright and Marc Forster, who I think are doing very interesting things. And Chris Nolan.