for all you categorization nerds:
i finally completed a huge project of retagging ~20,000 songs with detailed genre/location info in the "comments" section and it's working fantastically
my problem was that one genre field really can't encompass how i want to search through, listen, and group my music ... so now i just pack as much description as i want to into the "comment" field, and create smart playlists to search the fields
this works best for bands who cross genres or eras, like -- for example -- the beatles.
for "a hard day's night" i have the following tags (most from all music):
* Pop
* Rock & Roll
* British Invasion
* Pop/Rock
* Merseybeat
* Britain
for "magical mystery tour" i have:
* Pop
* British Invasion
* Psychedelic
* Pop/Rock
* British Psychedelia
* Britain
so i search (through smart playlists) for pretty much any kind of descriptor and come up with a perfect list of my music ... one of the coolest things i've found is listing the band's country/city, then being able to find all scottish bands, or all minneapolis bands, or all DC bands
i'm only about 1/4 of the way through ranking all my tracks, but once that's done it should be incredibly dynamic .... say i wanted to find all my 4+ rated American Underground songs from 1981-1985 from NYC bands, it's all right there
anyway, hope this helps someone, i know when i was first starting this whole thing i couldn't really find a good system out there, but i think this is as good as iTunes can handle