If you were worried about who would take over as director of The Hobbit with Peter Jackson only producing, worry no more: Guillermo del Toro, of Hellboy and Pan's Labyrinth fame, is currently in talks to take on the potential blockbuster, as well as a follow up feature rumored to be a story bridging the prequel to the Lord of the Rings trilogy.
However, one only has to take a look at del Toro's Imdb page to see that he will be an awful busy guy, writing and/or directing and/or producing eleven films in the foreseeable future (including the H.P. Lovecraft fantasy At the Mountains of Madness). And that's not even including the movies he's wants to make, such as his take on Frankenstein and a little movie called Harry Potter and the Deathly Hallows, not to mention this summer's Hellboy II: The Golden Army.
UPDATE: As Empire states, "Guillermo Del Toro is directing pretty much every film coming out between now and 2017": he also wants to direct a big screen version of another comic book hero, Doctor Strange.