Tim Burton? Goodness gracious me, no! Lots of black make-up, just for the sake of it? Johnny Depp as Bilbo, or more likely Gandalf? And the inevitable created part for ol' Big Hair herself, Helena Bonham-Carter? Gollum, perhaps?
No thanks.
Also, Del Toro's Pan's Labyrinth featured completely the wrong mood for the Hobbit, so I wouldn't trust him for this particular fantasy tale.
I'd prefer Kevin Costner, as director and to play the part of Gandalf.