Not that I'd want to take him away from the comics but I believe Geoff Johns would do well. He was Richard Donners assistant I believe so hes already worked in film. Otherwise I'm not too sure if being a good comic writer would necessarily make you a good movie director.
I don't necessarily think that "great comic book writer" equals "competent director". sometimes, that works out. but I have a very bad feeling about Frank Miller and his adaptation of the Spirit.
I really like the Spirit and the relaunch issues by Darwyn Cooke felt like a perfect blend of Classic Spirit, True-to-form Noir (note: not "dark grittiness", but noir) and just enough of the fun craziness. Frank Miller's interpretation (from what I've seen) just leaves me cold.
If it had to be a comic writer/creator like your question, I'd vote for Paul Dini, who is currently writing for DC (doing a great job with Detective Comics). Maybe team up with the great Bruce Timm and do an animated Spirit.
But for a true director/directing team, for the Spirit, (the best stories of which involve a lot of characters, a complex plot, a lot of ups-and-downs and what-have-yous...) I can't help but thinking it'd be the perfect comic property to fit the Coen Brothers. They'd never do it, but I imagine a great mix the crime and gunfight elements of "Miller's Crossing" with the approach of characters that made "Hudsucker" and "Lebowski" so unique. That'd make an awesome flick. I also heard that it was rumored that Brad Bird was going to do a Spirit adaptation for Pixar... I'd prefer that to Frank's vision...
Other dream director/property pairings:
-Brian K Vaughan writer
Danny Boyle director on "Y the Last Man"
-Screw Tim Story... I'd want to see a Joss Whedon "Fantastic Four" film. the FF work best as Explorers/adventurers rather than your traditional "superhero". have him adapt the first Dr. Doom story from the Mark Waid FF run.
(these are a stretch, but as long as we're dreaming here...)
Bendis - Writer
Scorcese- Director on "Powers" (cracking dialog, insane cases & violence, and a kickass soundtrack? sign me up)
(this is obscure, I don't care)
Evan Dorkin writer
Alex Cox (or Guillermo Del Toro) director for "Pirate Corp$/Hectic Planet" (it'd look like Blade Runner, but be full of loser delinquent misanthropes and aliens! awesome)