There are some topics open already for some the main new roles in Silver Chair:

Prince Rillian:
viewtopic.php?f=3&t=1177

Lady of the Green Kirtle:
viewtopic.php?f=3&t=1367

Puddleglum:
viewtopic.php?f=3&t=1174

Jill Pole:
viewtopic.php?f=3&t=216

But perhaps some consideration of some of the other more minor roles wouldn't go amiss? The Giants of Harfang, The Earthmen of Underland. Glimfeather even?

Would Timothy Spall be good for the voice of Glimfeather, do you think?

~Riella

Lady of the Green Kirtle: Kate Winslet
Puddleglum: Johnny Depp
Prince Rillian: Ian Somerhalder
Jill Pole: Unknown

My ideal Silver Chair cast:

Jill Pole: Dakota Blue Richards
Puddleglum: Johnny Depp
Rilian: Justin Chatwin
LOGK: Natalie Dormer

I can at least hope

OH, Dakota Blue Richards would be great! The Golden Compass wasnt a good movie, but she was the one thing that kept it from being a total disaster. But is she too old?

Nope she's a year younger then Will Poulter. Yes she would be fantastic as Jill!

I can't see Johnny Depp as Puddleglum. I know he could act it and everything. He just doesn't have the right look, and looking back at some of the other characters he's played, some people (especially non-book fans) might think the filmmakers are just trying to copy-cat Tim Burton's characters.
I like Frank Collison as Puddleglum. I think he would do it perfectly.

Jill Pole, I think, should be played by Lucy Boynton.

I think Cate Blanchett should play the LOTGK! She has the right look, and she made a fantastic villainess in Indiana Jones (which was actually the only thing I liked about that movie).

~Riella

Since we already have several open threads on roles in The Silver Chair, I'm going to go ahead and close this thread. Thanks icarus for posting those links!