I think to TV show does an excellent job staying close to the book. The biggest difference between the show and the book is the children's ages. In the book the characters are so much younger than what they seem in the tv show. I understand the change though because having 12 to 16 year old children running around killing and sleeping with each other would make for disturbing TV. The next thing i noticed after watching the first episode again is that when Dany and Khal first have sex is that she is crying. In the book she resisted it at first but then seemed to want it but in the show she seemed to dread it and almost feared it. Even in later episodes Dany constantly looks for mental support through the dragon eggs where as in the book she seems so much more independent and accepting of Khal after the wedding. The theme of Dany being sold as a child bride is still present in the TV show and actually is seem more serious. Theon also plays a much larger role in the TV show than he does in the book. Finally the largest difference is the amount of nudity in the show. I think the writers put the nudity in to attract a larger audience and draw more attention to the show itself. The nudity isnt necessary at all but i understand why the writers would put more of it in the show.