I'm in the process of retraining my brain: from now on, I'm going with "toilets" as my word of choice. Yes, much of this comes from being awash in a sea (a somewhat annoying sea when one is using lots of indices and databases) of changing terminology for public facilities over the course of the 20th century, but it is more than that. First, as I've already gone on about in other posts, I think we should label facilities not by who should use them (if they are truly public facilities) but by their function/equipment, which I think "toilet" represents. Second, it pokes at American's delicate sensibilities about elimination by referring to the space by the fixture into which we eliminate (okay, it works less well for urinal-only users... suggestions?). My thinking is that until we (that would be the collective, societal "we") can get past our studied silence about this topic (the fact that people need to pee, poop, change tampons, etc), we aren't going to do a better job about providing truly public facilities for the public good. So, from now on, when I "need to excuse myself" (as my mother taught me to say), I'm going to ask for the toilet.
"men"/"women" (or the many equivalents)
water closet or WC