Essentially, the Playlists are grouped in to conceptuals, I use _'s to force the order to reflect what happens when you first process. There's Groups for Processing, Directory ( they are general Genres ), AMG Sub-genres tagged at an Artist Level, Artist Origins, Artists ( I like to track sidemen ), Album aspects, Album qualities, World Styles, Song < Instruments, Modifiers, Mood, QUality, Style, Temp, Theme, Timbre >.
Processing contains things like what remains to be done to the file as far as tagging goes. Artist Origins is quite literally continent, region, country, state, city. Album is heavily used as it indicates if this is a complete, incomplete, Anthology, Collection, Debut, Period Piece, Pinnacle, Sountrack, source, swansongTribute etc....
World styles differ from Origin in that they are cultural or musical styles within the country/region. Song indicates BBC, Bootleg, Cover, Dub, RemixCover ... Modifiers are verbs to apply to the subgenres, modern, traditional etc...
The others are pretty predictable... by being playlists I can make smartlists that include & also exclude use AND or OR quite nicely, limit by dates... You can keep adding them as you think of them, it works wonderfully. I use AMG as the rule to go by, but at song level my ratings and categories take over. I even tag by my friends tastes and you can set up random selections that are the intersection of their likes and have acceptible mixes on the fly.
So you can see it is nice to describe these playlists and still enjoy the fact that all my songs have reviews & biographies plus musician on the albunm inside the notes.