For D&D, most of my group seems to prefer "DM", but we all user "GM" everywhere else. Myself, I don't see much point in swapping terminology for the same role just because you changed games.
So, DM, Storyteller, Mythguide, Controller, etc. are all "GM" to me. About the only alternate name I use with any regularity is "referee". I use that to underscore the neutral nature of the GM. My role isn't to oppose the players or to spoonfeed them. It is to arbitrate the rules (of course there's more to it, but this aspect is the one that so many people seem to forget).