Regarding e-Books and more general file formats (except audio and video as of MM 4.0) I would suggest you "Whereisit" as must have app.
Thank you for the advice! I tested "WhereIsIt" and there are some nice features MediaMonkey and Calibre don't have, specially the very useful handling of "offline files" (Files on servers, CDs, DVDs, HDs you are actually not connected with). But "WhereIsIt" is far away from being a replacement for both. Some reasons:
1. "WhereIsIt" doesn't handle the Media-Information in Field-Structures (or I did not find out how to do it: It handles lot's of different Media with flexible PlugIns, but most the extracted Information is stored together in a single text-field as I understood it, whereas MediaMonkey has lot's of music-related fields and Calibre allows the user to create as many user-defined fields as he wants),
2. "WhereIsIt" has nor reordering-file-management like MediaMonkey
3. and worst: "WhereIsIt" is not helpful to consume, transfer and convert media: I understood that it is meant to be only a "dead achieve" not a media-handling software like the other.
You need all three (Calibre, MediaMonkey an WereIsIt) to have all advantages and in my opinion "WhereIsIt" is the one that I could do without most easy. Perhaps I didn't invest enough time to find out all advantages of "WhereIsIt", but I think I found out enough to see that there are elemental gaps against Calibre an MediaMonkey: So two tools for media are more than enough, but three are not acceptable for me.