One kind of book I love is where authors combine historical fiction with light fantasy.  Under Heaven by Guy Gavriel Kay, which I am reading now, is an excellent example of this -- as is another of his books that I read a few years back, Ysabel.

Under Heaven is described as being set in a "reimagined" China during the Tang Dynasty.  I don't know enough about the era to know how much is based in real fact and how much is "reimagined," but there is an air of the fantastical about it from the very beginning: The main character, who has been burying the dead on a huge battlefield for two years as penance and a way to honor his deceased father, and he has been living with the ghosts of the dead for all that time.

Then there are the enigmatic female warriors that keep cropping up in the story.  The book's setting has been compared to the fantastical world of Crouching Tiger, Hidden Dragon, and I have to agree.

It takes a lot of skill as an author, and a lot of knowledge of the true history, I think, to successfully combine history and fantasy like this.  Ysabel showed the same skill and historical knowledge as Under Heaven.  In Ysabel, a young boy and a friend discover spirits in Paris who have been warring over the love of a woman for millenia.  Although the story itself takes place in present-day, there is much in it about the history of Paris and the spirits.

I can think of other books that successfully combine history and fantasy, but none come to mind that are as compelling as Kay's books.  If this is a concept that appeals to you, I highly recommend both Under Heaven and Ysabel!