Re:Best fantasy world
What is the question? The best conceptualization, or the one where you would like to hang your hat?
For conceptualization I would have to go and re-read all the books to decide which is done better. When you can feel that every question you have could be answered, that would be the best.
As for hanging my hat - I'll go for the Alan Dean Foster Spellsinger series. I would love to live in a world where animals are on the same footing (pawing?) as humans. It just fascinates me.