This is an interesting and important topic to me, as well, and unfortunately one that requires a little follow up in terms of what you want the catalog to do and what skills y'all have in your group and how much time folks can put in, now and ongoing.
Milo Miller from QZAP writes:
If they're going to be doing ILL and playing with more traditional libraries, care about MARC, etc. and have someone who can do the implementation, I'd tell them to take a look at Koha
I'm still super jazzed about Collective Access, and think it might be a good solution as well.
I'm guessing that there's probably also a way of doing implementations through Drupal, LibraryThing (though I'm pretty sure it's not FOSS [It's neither free as in speech nor as in beer for more than 200 items cataloged, but it is an easy solution--Jenna]), or maybe even just building good databases with LibreOffice?
Eric Goldhagen, the developer of our site follows up:
First they need to better define what they want, a website with information; a catalog that has MARC data and can handle things like circulation; a searchable archive of their collection using complex metadata?
if they want primarily a way of having an online catalog that is informational and using non-controlled vocabularies, a CMS is the right way to go (drupal, joomla, wordpress, etc.); if they plan on handling circulation they need to think about an ILS like koha or evergreen (and I'd lean towards koha); if they don't circulate and want easy to use complex metadata, then a collections tool like collective access or omeka is the way to go (and I'd strongly advocate for CA over omeka).
The most important thing to keep in mind is starting with a tool that is already moving in the direction they want, even if they have a drupal wizard, I'd caution against trying to make an ILS using drupal. Find the right tool and dev community that syncs with the project.
Me again: please follow up as needed!