It really depends on the context.
I always disliked the older D&Dism "magic user", even when I first encountered it at the age of ten or so, because it felt awkward and pedestrian. "Mage" works pretty well, though again I've always felt its use as a term of address was clumsy and far too common in D&D-related fiction.
"Wizard" and "sorcerer" strike me as fairly reasonable in-character terms for those aware of the difference between learned and innate casters; by contrast, "arcanist" strikes me as inappropriate except for those who appreciate the distinction between divine and arcane magic on a level slightly more elevated than "the guy on his knees and nature-girl over there pray to gods for their spells, and these other people don't".
For instance, I wouldn't necessarily assume that anyone other than sages (and members of the classes in question) understands that wizards, sorcerers, bards, assassins, hexblades, beguilers, dread necromancers, warmages, et cetera all make use of arcane magic. There may be no identifiable similarity between their spellcasting abilities from the layman's point of view.
(On that same note, since the association between clerics and druids would be on the basis of "these guys are religious", divine minds and ardents might get lumped into that same category because of their devotion, and other psions might be thought of as similar to wizards and sorcerers - at least by laymen.)
"Magician" is too gauche for my tastes. It seems to me that the collective term would default to "mages", as long as we don't have any calling-you-by-your-category instances of "Come here, mage!" and "Not yet, warrior, I'm busy!"