Wow, first things first this book was very long. I even thought I'd be bored in the middle and end up not finishing this, but I didn't get bored, and I finished it happily.
For a fantasy book to be good, for me, it needs 2 elements. One, a very good world building, and the second is very good characters. Either one of the two missing and the novel wouldn't turn out as good as A Game of Thrones.
I have to point out how much I loved the characters, and I also have to add how attached I am to almost everyone. I've heard numerous warnings telling me that I shouldn't be, but how could one be not? George R. R. Martin has truly written a novel that we will never forget.
My favorite character has to be Jon. He may be the bastard, but I don't know why I like him the best. My least favorite is Daenerys. At first I thought she would be a useless character, but in the end I realized how important she was to the story. That ending made me want to read the second book right away.
To sum it up, and before I spoil anything, this is a book any fantasy reader should read. Very good world building, and characters you would love till the end. Yes, the book may be very lengthy, but in the end you'll be asking for more, and thankfully, there are 4 more available as of right now. Don't be discouraged because of all the hype this book has received, I know how hype mostly leads to disappointment, but believe me when I say you will not regret reading A Game of Thrones.