The following is a short list of my favorite Christian fantasy authors:
1) Stephen Lawhead
2) Karen Hancock
3) Patrick Carr
4) Jill Williamson

Feel free to add your own favorites below.

Agree about Jill Williamson - I've only read 2 of her books so far but they both blew me away and added her to my favorites list without question.

I haven't read Patrick Carr yet but he's on my list and I know people who rave about him so I fully expect to love him too.

They each only have one book out so far but I majorly loved the books enough that I will snatch up whatever they publish next without batting an eye: Sarah E. Morin (Waking Beauty) & S.J.Abraham (Terra Soul).

I really enjoyed Heather L.L. FitzGerald's Tethered World Chronicles. John Otte, Kathrese McKee...

My favorite Christian fantasy author is a bit more obscure... Coleman Luck published a Christian adult fantasy novel by the title Angel Fall. (Right now only his expanded author's edition is available new, although you can get the original edition published by Zondervan used if you know where to look. I haven't read the expanded author's edition yet, so I can't vouch for it.) The original version changed my life and the way I look at Christian fiction and what it can be. It's not a fluffy adventure fantasy. Although he's not graphic (i.e., no sex scenes for the sake of having sex scenes), there's a lot of surreal-horror imagery and he deals with serious subjects like childhood abuse. But it is so raw and real and made Jesus more real than any other "Christian" fiction book I'd ever read.

Also the author is a sweetheart and I still talk to him on FB sometimes.

Jill Williamson and Patrick Carr are both great.

I especially like how Patrick Carr uses religion is his stories. He's got a very institutional church that is central to the plot. It cannot be removed without destroying the whole thing. Yet, within that he is not heavy hitting with the religious concepts. I'm not fond of highly hierarchical churches, but I have no problem with how Carr uses them. He shows the mix of good and bad that come up anywhere.

I'm also particularly fond of Jaye L. Knight, Tricia Mingerink, and Kendra E. Ardnek.

Jaye and Tricia both write fantasy books with a persecuted church focus, while Kendra does a lot of different things. She's one of those authors who can't focus on a single thing, but she's also a dear friend, so I deal with that.