There are quite a few book recommenders based on HN data. This recent one came to mind:

Top 30 books ranked by total number of links to Amazon in Hacker News comments http://ramiro.org/vis/hn-most-linked-books/

I am surprised that someone doesn't solve this problem once and for all by allowing decent search parameters (e.g., all time, last month, by karma, by genre, etc.).

This latest submission weights by karma and bins the results weekly. Those restrictions make it personally unappealing but it is a great first step. I wouldn't have thought to consider karma.

Edit: clarity