Now obviously you have the SW books, and the SoIaF books every loves, and discussion is open on them. But this is also open to any kind of books.SciFi or high fantasy, fiction and non fiction, biographies or spoofs (al la pride, prejudice and zombies), IT MATTERS NOT!
Two series that I absolutely love are the Sword of Truth series, and the Chronicles of the black company.
Sword of truth because Terry Good kind does an amazing, masterful job of drawing you into the stories. He makes you care for the characters, makes you see the environments he's writing about, and does a great overall job of just setting everything up. Those that watched the shows, the book series is no where near as disjointed and muddled as the show. Its an absolutely great book series, and one I always suggest. Hell, it was the series that got me to start writing.
The series follows the adventures of Richard Cypher who, on the day trouble visits three, is thrown into a war that has implications for both the known and unknown worlds. Magic, plots, wars, all have a way of tearing factions and alliances apart, or forming new ones. Kingdoms fall, empire rise, and everything rests on the back of a woods guide from a land with no magic that has a past that even he won't be able to believe when he learns of it.
The other series, the Chronicles of the Black Company, is a odd series but at the same time absolutely amazing. Written from the perspective of a annals or Lore keeper, the last free company of Khvotar or better known as "the black company", is a group of mercenaries who can't seem to keep a honest retainer. Bouncing from battlefield to battlefield, picking up recruits just as fast as they die, the black company gets thrown in a centuries old war between wizards and sorceresses that have powers to do nearly everything you can dream of, and even the focus of nightmares.
Again, a great read that draws you in, you get to know the characters on the most personal level out of any story I've read so far. If you like fantasy, its a book series I would suggest.