As a matter of fact, I was just talking to someone about Sin City and how much it grew on me. Walking out of the theater, I felt like I'd been given a physical beating - its so dark and brutal, it took me several days to decide whether I liked it or hated it. I only went because it was written by Frank Miller who wrote some great Batman stories for the comics - I didn't realize until later that it was produced and directed by Robert Rodriguez, who's a protege of Quentin Tarantino, who's 'fountain-of-blood' theatrics have never impressed me. Having seen Sin City several times now to absorb the nuances, I think its a great piece of cinematic art, comparable to Kubrick's work in Clockwork Orange. And the best job any director has ever done of bringing a comic book tale to life.
Rodriguez strikes me as much more creative in approach than Tarantino and just an all-around smarter filmmaker. Speaking of odd films, Rodriguez also did Planet Terror which is a hilarious dark sendup of 60s/70s low budget drive-in SF movies. The gory gross-out gags are a little over the top sometimes but if your sense of humor is sick enough, its full of giggles.