I don't think I have any fantasy authors that are really influencing my games. My games are probably more influenced by old Dragon articles and earlier editions of campaign settings or generic source books than any fantasy author.
I ran through as many as authors as I could think of and I don't recall any that had any sort of overt influence on my games.You do, you just don't realize who they are.
I'm more into mythology, in which case I'd have to point to Mesopotamian, Egyptian, Greek, and Indian history/religion/myth/folklore as my biggest personal inspirations. I also read lots of stuff related to myths from around the world and myth in general. That and the Old Testament.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.