My favorite series is The Farseer Trilogy and the Tawny Man Trilogy by Robin Hobb (both trilogies are tied together so technically they are apart of the same series). I love her books. Most of them are character driven with intricate plot lines. What I love most about them is that the main character is human. He isn't perfect. In fact, he is one of the most flawed characters I've ever read. The image below is the first book in the series.
Heh, I was obsessed with Tamora Pierce in middle and high school. I still have fond memories...
Wicked, closely followed by Harry Potter.
This question is actually unreasonably hard for me. My favorite Fantasy Author is Piers Anthony and Series wise I'd probably say that the "Mode" series is my favorite or "The Incarnation of Immortality".
The Incarnations of Immortality have an amazing concept if nothing else, they work off ideas like father time and death are jobs and positions that mortals get designated too and have to work together and do their vastly important jobs while dealing with real personal problems.
I also Enjoy Bizzaro books quite a bit, Which share some grounds with fantasy books, so if those count my favorite fantasy book would be "Adolf in Wonderland".
How About Enders Game?? i mean i guess its more sci fy than fantasy, but it really does take place in a different world. it is beyond excellent writing and very character driven. also what i love is that there are so many books, so i wont run out too fast. i could not put these books down, no to eat sleep or even study.