Hi SRG,
From a technical perspective, I would say FileMaker is not overkill for smaller databases. I have plenty of FM databases with just one or two tables and maybe just a few hundred records.
From a price point of view, that depends. FM costs significantly more than what Bento did, so you'd need to crunch the numbers. Of course the benefit of FM is it can *do* significantly more than what Bento can, and you would have the flexibility of expanding and enriching your book database, and maybe creating others. Container fields, for instance, especially in the latest version of FM, lend themselves nicely to cataloging.
Cheers,
Brad