I haven't settled on perfect organizational strategy yet but what I have is:

Artist -- list of all artists, and in each artist is a list of all songs by that artist. No albums.

Albums -- list of artists -- in each artist playlist is a list of their albums -- in each album list of their songs in track order

Composer -- Classical, Jazz, Opera, in each category is a list of composers falling into those genres, and in each composer playlist is a flat list of songs composed by that person, regardless of who is rendering it. (i wish the empeg had a way to differentiate composer, conductors, bands versus soloists, etc, and be able to search by/tweak by those, oh well!. this is an approximation).

Moods -- Here I am still experimenting with "Blues" "cool" "deep" "50s" "fast" "funny" "sappy instruments" "sappy voices" "sleepy" (point is, you get into a mood, you want to play by mood).

Genre -- Here I have genres (Acapella, Blues, Classical, ...) In each genre is a flat list of songs of that genre.

Audiophile -- Here I have an ordering of audiophile related material by album (e.g. Stereophile CD1, CD2...etc) and then categories by: Bass, Breath, Detail, Dynamics, Highs, Layering, Soundstaging, Live, Vintage, and non-musical test noise.

I'm working on a new one for dance related stuff:

Rhythms: Swing, Cha Cha, Foxtrot, Mambo, Menrengue, Samba. ..etc -- flat list of songs that fall into rhythmic categories.

I have some odd ball mp3s that do not fit in my system. I have a big collection of commercials ("Coke is it!") and am planning on adding popular speeches, as well as other non musical recordings. Also, in there are relaxation related tracks. Luckily, wendy filters came in just in time to help filter on the road.

Am I helping or hurting? ;-)
Calvin