When I first read this question, I assumed the answer would be
simple.  I see, however, that even the simplest things, when interpreted
by many, become complex.  So let me add to that complexity.
        It seems to me that those people wandering through our spaces are
"visitors"--'cause they're, well, visiting (though I hear some stay
overnight to pick up souvenirs).  Some have visited before, other not;
some are world weary museum goers, others first-timers; some are taking an
hour off during a business trip, others planned to come for the day during
their annual vacation (and so on).  Once they pass our portals, the fact
that some come from near and some from afar doesn't make them "different."
For once inside, that broad visitor/tourist distinction disappears and new
distinctions appear:  some become students, some strollers, some streakers
(with apologies to whomever I stole these from -- George MacDonald?).
        As a sometime museum visitor myself, I'd rather be thought of as a
"visitor."  "Tourist," I agree, has taken on a pejorative ring --
"traveller" is nicer.  "Guest" makes me uncomfortable 'cause then I think
I have to behave.

Kersti Krug
Museum of Anthropology
The University of British Columbia
Vancouver, Canada