I have have had many favorites over the years, from Laura Ingalls Wilder as a child, to Beatrice Small And Jude Deveraux during my romance phase, to Anne Rice as I discovered vampire lit, to Laurell K Hamilton until she started writing porn, to Kim Harrison and Jim Butcher.
At this moment my favorite would have to be Sophie Littlefield. Every book of hers that I have read I loved. Her characters are funny and intelligent and flawed. Her stories are exciting and charming and fun to read. When the Aftertime trilogy ended I cried, not just because of the ending but because I would never get to enjoy those characters again, and her Bad Day series is just wonderful.