I've added a couple more bits of Ajax to the OPAC, although they've not live yet:
- links to items with the same (or similar) subject headings
- links to related works / other editions (courtesy of OCLC's xISBN service)
As an example, here's the links that appear for the first edition of Learning XML:
Although having links to "people who borrowed this" is cool, it does tend to link to items that circulate well (which you could argue is a "good thing"). On the other hand, the quick links to items with same/similar subject headings are deliberately shown in a random order.
[...] this also borrowed…" suggestions (more info) 4) books with similar subject headings (more info) 5) other editions of books (more [...]