I went for "other". I am a better player than DM, mostly because I am still pretty new to DMing, but I like being either a player or a DM about equally, they're both a lot of fun.
I was a game moderator and keeper-of-the-rules before D&D came out. I started out as arbitrator of miniatures battles, as I disliked actually playing them, due to the level of animosity that often arose. I also was the "last word" for many rules questions in AH/SPI boardgames.
So when D&D came out, I just segued on over...
While I am usually the GM, and greatly enjoy that role, I do appreciate that my gaming group is willing to take "times out" wherein someone else will run a game for a couple months, thus allowing me to play.