Spider-Man 2 was the first, and to this day the only movie I ever saw twice at the cinema. I didn't think it was perfect or anything, but it was a fun enough experience to get me to go with two seperate sets of friends and watch it.
I liked Hellboy as well. There was just something about it that got me into the story.
I haven't been following its developement, but I hope Sin City surpasses both of them. The trailer was awesome, and I think the movie might fall into that category as well.