Okay. Low to moderate light, upright plant, not huge at maturity, somewhat humid. Well . . .

Aglaonema spp. (Chinese evergreen): can get tall, but this takes a while, and you can cut them back whenever. Lots of different cultivars out there. I'm currently in an argument with one of mine ('Stars'), but I have several others ('Maria,' 'Golden Madonna,' 'Pattaya Beauty,' 'Silver King') that are very laid-back and friendly.

Anthurium spp. (flamingo flower): this one might be better with supplemental light, but they do well with added humidity and don't necessarily get huge, plus, if they're really happy, they've got neat, long-lasting flowers. Pick your cultivar carefully.

Aspidistra elatior (cast-iron plant): They're not fast growers, or especially showy, and I found mine to be magnets for spider mites. On the other hand, they are happy with low light, and slow growth means they stay whatever size you buy them at for a long time.

Asplenium nidus (bird's nest fern): another one that would really prefer bright indirect light, but they're not especially difficult and they would enjoy the humidity. Given enough time (like years), they can get big.

Chamaedorea elegans (parlor palm): has the advantage of being buyable in any size, and doesn't mind dim light. See also C. metallica.

Dieffenbachia spp.: there are some small cultivars that are quite nice, and they have that tropical "look." I hear nice things about 'Tiki.' 'Neptune' is one of my curent favorites. 'Camille' you can find anywhere.

Epipremnum aureum / E. pinnatum (pothos): One of the easiest plants to grow, under any conditions. It does grow quickly, but could be cut back to fit the space. The 'Neon' cultivar is awesome.

Ficus binnendijkii (AKA F. alii, F. maclellandii, F. longifolia) (long-leaf fig): Has the growth habit of the standard ficus tree, but longer, willow-shaped leaves. Also seem to be a lot less fussy than F. benjamina. Brighter light is, again, better than dimmer light, but they're reasonably flexible (mine's done well in a north window).

Maranta, Calathea, Ctenanthe, Stromanthe spp.: these are all gorgeous plants, they love (in fact, *require*) additional humidity, and they don't get huge. Light might be an issue for some species. I don't recommend them: they're divas. Everything has to be *exactly* the way they want it, or they throw leaves, or the edges of the leaves turn black, or they're covered in spider mites overnight, or etc. etc. Other people around here will find this an exaggeration (and maybe it is), but they do have a pretty high difficulty level, all the same. If you *must*, Marantas (prayer plant) are the least diva-ish, is my impression.

Philodendron 'Moonlight:' I have two in my own bathroom, and they love the humidity in there, though I also have a supplemental fluorescent light on them so that may or may not work for you. If you don't like the color, there's also P. 'Prince of Orange,' P. 'Black Cardinal,' P. 'Autumn,' and so forth. P. scandens or P. scandens micans might work better if supplemental light is not a possibility.

Rhoeo discolor, R. bicolor (Moses in the cradle): I don't have any direct experience with these, but the size is right and they're not supposed to be excessively demanding.

Sansevieria trifasciata (snake plant): doesn't need the humidity but probably wouldn't mind it either. Might rot if it got *too* wet.

Spathiphyllum spp. (peace lily): No problem with light or humidity, and the size won't change a whole lot from whatever size they are when you buy them. I don't really see any problems there except that you say you've got one already.

Zamioculcas zamiifolia (ZZ plant): Also prone to rot if too wet, but the light would be no problem, and they're slow growers.

Mr. Subjunctive...thanks so much for the fabulous list. I'll copy the list and take it to the nursery with me.

I wish I were as knowledgeable as you!