Who's Returning for The Hobbit

Many of the characters from Lord of the Rings will be back for The Hobbit.  Obviously Bilbo (Martin Freeman/Ian Holm) will be back since this story is about him finding the ring.  Gandalf (Ian McKellen), and Legolas (Orlando Bloom) will be included in the cast of The Hobbit as will Gollum (Andy Serkis) and Saruman (Christopher Lee).  Some of our elf friends will be back including Elrond (Hugo Weaving), and Galadriel (Kate Blanchett).  Missing from the elf line up is Arwen (Liv Tyler) who was not in the original story "The Hobbit" so that makes sense.  Actually, most of her part for Lord of the Rings the movie was taken from the appendices in  the books.  I guess otherwise it would be mostly a guy film without her and Eowyn who also had a bigger role in the movies.  I don't know how they will work him in but Frodo (Elijah Wood) will be back for The Hobbit.  Frodo was not originally in The Hobbit story by J.R.R Tolkien and since this movie is a prequel to Lord of the Rings I am not sure what his role will be.  I guess we will all have to stay tuned...