Talking to Sci Fi Wire, Ian McKellen (Gandalf) says that he has finally had a chance to read the script for Guillermo del Toro's live-action adaptation of The Hobbit ... and he "couldn't be happier" with it. And why shouldn't he be, since the part was written specifically with him in mind:
As Peter has said, they loved writing Gandalf [for The Hobbit] because they knew who they were writing him for. ... There are a lot of characters in The Hobbit, including, crucially, Bilbo, and they don't know who's going to play Bilbo. So it's extremely attractive that this part has been written for me. The other Gandalf was written for, well, just as Gandalf. There's lots for me to enjoy, in all sorts of ways. And I couldn't be happier. But I'm sworn to secrecy. I'm not to say anything at all about the script.
McKellen goes on to offer some reassurance about the continuity between The Hobbit and the Lord of the Rings now that it is being helmed by del Toro, rather than Peter Jackson:
They are the same person. ... They were separated at birth. They're twins. They have the same attitude. Neither likes working in Hollywood. They're both fascinated by fantasy and violence on the screen, and gore, and things that frighten you. They like going into the psyche. They're both brilliant storytellers in very much the same way. And I think the script, because I have read it, plays very much to Guillermo's strengths, as I've seen them. I have seen his other movies, and people act very well in them. So I think it's all fine. And Peter will always be there.
Hopefully, this is all a signal that casting can now begin in earnest. Who's going to play Bilbo? Inquiring minds want to know.