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I think you'd gain a lot by:

1) Show the last 200 searches that people had made (or the most popular for the past day, week, etc.)

2) Instead of directly linking to Amazon upon clicking a book/product, perhaps you should fly out some hidden details for the item (not ajax if feasible).

3) You could also have a "Search by Author" and "Search by Topic" link that is provided when you click a book that provides more results with content.

4) Maybe allow people to create book shelves that they can explain the grouping of a set of books and why they go well together (etc!).

5) One last idea: Provide a list beneath that has a tiny bit more info - as they scroll left/right in the top list, have the bottom scroll up/down to show the range that is visible. This would help with you only linking/showing 20 or so results at a time if you let the list (text) show 100 or more.