But I wouldn't want Ian McKellen back... I really didn't find his portrayal exceptional (preferred another Shakespearean knight, Michael Hordern in the radio version ) and hearing his voice inthe trailer for The Da Vinci code ..I just hought "its gandalf talking to Frodo again.." .. may be another Ian ..Ian RIchardson would be interesting.
I think Jeremy Irons would be a good choice for the Master ... . Or how about Rufus Sewell..?
I would have my darling Hugo back as Elrond and wonderful Bill Nighy as Galion the butler.
Jason Isaacs as Thranduil would be wonderful I think and maybe Paul Rhys as Bard the Bowman - though he could be an elf the book does say the Elvenking was golden haired.... if I am not allowed Hugo back, he can be Elrond and Toby Stephens or Hugh Jackman can be Bard.
I am really struggling with Bilbo - I am trying to think of someone who is about the right generation and type .. My best attempt is Michael C Hall who although not a perfect match physically has that wonderful ability to play complex characters sympathetically and believably. I can't think of anyone better to get both the Took and Baggins traits across ... but others may, and get a better physique du role.
Thorin - I would choose Simon Russell Beale
here
Bofur would be Richard Griffiths
Beorn ...is it possible to get beyond Brian Blessed?
Alan Rickman would be fab as voice of Smaug if he could be borrowed from HP