I just finished issues 1-20 of Immortal Hulk by Al Ewing and Joe Bennett. It was most excellent, rather horrific for a superhero comic. It was more violent and gross than most stuff Marvel puts out, but I liked it. The art was a perfect match for the writing. It reminded me a lot of Alan Moore’s Swamp Thing run and in the afterword the author mentioned that as an inspiration.
If you’re looking for a Marvel series that crosses over with horror, I can’t recommend Immortal Hulk highly enough.