Weird I know, but IMO it's best to hand curate books and music (I have comics not manga, but same deal there). Automated tools can quickly rack up more books than you'll read in a lifetime, and enough new music to listen to for a decade fits in a TB (even mostly FLAC). The problem then becomes finding what to read / listen to next, which gets worse with size.

That said, having a large local nonfiction book / journal article library can be useful to grep through, especially given current internet search problems.