What are the best *D&D books and/or modules to get a hold of?
This depends on who you ask. Everybody has their own opinions on which products are great and which are trash. However, there was a survey done by Anthony Brooks on rgfd and ADND-L of every *D&D product TSR had ever put out, as of around January 1995. It rated each product on a 0-10 scale, based on the average of all of the responses, and included comments on the products by the people who responded. Only those products which received 5 or more votes appeared in the listings, but there were comments included on several non-listed products.