Well I worked through the entire (original, by Fleming) James Bond series. Twelve (I think) novels; I'm a big fan. Different from the movie, but I liked them.
Now I've taken the plunge: I'm 75 pages in to A Game Of Thrones. I've seen the series, but MAN, the book is so rich with detail, even though I (think I) know everything that's coming, it's so engaging. I'm loving it so far. I'm not a fan of the two gentlemen that produced the series (my daughter and I just refer to them as "the two db's") and each page hardens my resolve on that. They did a lot right (at least so far; I guess I'm two episodes in, AT BEST!) but whether it was me or the scope or the presentation, there was so much nuance lost, IMO. (One example: it never dawned on me that Catelyn would not only want Jon to join the Black so she didn't have to see him - and her husband's infidelity - on a daily basis, but that he would not be able to sire children to compete with her own for Winterfell. Two: the wanderlust of both Bran and Arya is far more evident in the books. Maybe it was the kid actors, but I just sort of got the impression they were brat kids in the series, but the logic and connection of their points of view to each other and to the Stark line is far more clear. I disliked Bran intensely in the series and never warmed to Arya, but I sense that might be different in the books.).