This is my tree structure:

By Artist
....10000 Maniacs
....4 Non Blondes
....[...]
Soundtracks
....Cinema
........2001 Space Odissey
........Pulf Fiction
....TV
........A-Team
........Magnum PI
....Cartoons
........Goldrake
........Mazinga
by Taym
....Latest
....Rock
....Blues
....Country
....50s
....60s
....[...]
....80s
....90s
....Blue Mood
....Classica
Special
....Non music audio files (voice recordings, etc.)

After testing for a while this was the most intuitive structure for me. So far.