What Is The Magic Number?

How many books would you have to include on a list of favorites to be certain you wouldn't leave off any important ones?

An author I admire got me started on this by listing twenty five of his favorites and suggesting the optimum method for completing it was to do an automatic writing exercise. That number and that approach presented me with two immediate issues: 1.) My bias for fiction made my quickly constructed list of twenty five very lopsided and... 2.) The egalitarian in me had difficulty allowing more than one book by any author on such a short list. A solution? Double the number.

Fifty favorite books helped with issue #1 - non-fiction and fiction have started evening out. However, issue #2 persists. Limiting some authors to even two books among fifty still leaves my list woefully incomplete. And, I haven't even consulted my reading journals yet - I'm still in automatic writing mode. Is one hundred my magic number? What is yours?