If you enjoyed George R.R. Martin's
A Song of Ice and Fire, I would recommend Robin Hobb's novels. I discovered her because Martin confessed in his blog that he is a huge fan of her work. And it's easy to find things they have in common: they are both excellent at creating plot twists, they are very good at characterization, and their fictional worlds seem quite authentic. However, Hobb focuses on one character, so her world is not as rich as that of Martin, or at least is not presented from so many different perspectives. She has a clear advantage over Martin: she finishes her trilogies. And, like Martin's books, I couldn't put any of her novels down until I finished them.
The order of the first trilogy is:
Assassin's Apprentice (this book used to be a freebie, but not anymore, it seems
)
Royal Assassin
Assassin's Quest