1. 1600 books down! Only, er, 3400+ more to go.
2. The ISBN search, while annoying from a typist's perspective, is nevertheless far more efficient than the title/name searches. This is especially the case when entering older editions of Penguin Classics or Oxford World's Classics.
3. Somewhat oddly, I'm finding Amazon's catalogue to be marginally more useful than LOC; it's much more likely to have that random book in Everyman's Library.
4. There are some strange returns in the searches, including mismatched titles, authors, and ISBNs (e.g., Robert Peters and Peter Allan Dale "authoring" each other's books).