I think we should popularize "Selene" as the scifi name for the moon, the name people would use when "the moon" might well mean Enceladus to some people.

"Luna" is relatively well-known and all but it always sounded a bit off to me, it doesn't sound planet-y..
But maybe that's just because i'm swedish and it sounds like a verb to me. "Jag måste hem och luna mitt marsvin"