I'm using a flat directory structure.
Scratch that. I have finally given in to convention and reorganized my library to have each album in an individual subdirectory. MC and other software prefers and expects a library to be organized that way. I give in and will stop trying to swim against the tide.
The turning point was me getting an iPod Classic. The Compilations feature wouldn't work with my old naming system. MC will only support the Compilations on an iPod if each album is in an individual subdirectory.
Earlier this week I did a mass rename/reorg and my filename scheme is now:
Directory rule: [library]\[Album Artist (auto)] - [Album]If(IsEmpty([Disc #],1),,-PadNumber([Disc #],2))
Filename rule: Mid([Album Artist (auto)],0,20)-Mid([Album],0,20)-If(IsEmpty([Disc #],1),,PadNumber([Disc #],2))-PadNumber([track #],2)-Mid([Name],0,20)
[library] is a custom tag that I use to organize the file in directories by very general genre. It contains general names like "rock", "jazz", "classical", "blues"
MC makes it very easy to do a mass reorg like that.
My complaint with the new reorg is that some of the directory names can be a bit long for some of my classical albums and a few other albums. I could limit the length with a Mid(). I'll have to think about that.