I've only read through about 2/3 of book 3 (I've got the next 2 books waiting, but I have not been in a reading mood lately, so who knows when I'll finish). I felt the first season did and excelent job of getting the feeling/atmosphere and major plot elements of the book. My only complaint was/is that the dire wolves are far smaller on screen than the in book descriptions would lead one to believe. Season 2 will add some new characters that I'm very much looking forward to seeing and hearing (and a lot of them should be in the first episode since they are introduced in the first chapter of book 2).
I felt the casting was good, in particular, Peter Baelish, Varys, Eddard, Arya, Tyrion, Tywin, Jamie, Cersie, Joffrey and Viserys were all a very good match to what I envisioned from the books.
Jon Snow and Daenerys were quite different from what I imagined for appearance, but I think the actors for both of them have done a fine job and still capture the essence of the characters.
[MENTION=10757]Nicodemus[/MENTION]
Which characters do you think were poorly cast?