QUOTE(milesmonk @ May 4 2008, 18:01)

I'm concerned not so much with the file/folder structure, as with tagging. Who should be "Artist" for a a Classical performance? Sometimes it is the performer who is the highlight (e.g., Glenn Gould/Luciano Pavarotti), and sometimes it is the piece being performed that is the star (e.g., a second-rate philharmonic performing Beethovan). Sometimes, it is the conductor who is given top billing. How do you tag it, and how do you organise/display/sort it in your player of choice?
The ID3 tagging scheme was devised by geeks who didn't know or care
anything about music. It's crippled in many ways, ONE of which is that it has no built-in universal support for subtags or multiple or'ed-together values of the same tag. I put ALL of the stuff you mentioned in the "Artist" tag - ensemble, conductor, soloist(s), etc. But that still doesn't make it easy to display on my iPod for, say, all the tracks featuring Alfred Brendel or all the works featuring the Chicago Symphony Orchestra, if any are the same tracks, unless I do a manual search (and thank god for
that feature on the iPod!).
Likewise "Genre" needs to accept multiple values. The same piece of music could reasonably be more than one genre - rock and Latin, Latin and jazz, jazz and classical, pop and soundtrack, etc.
And classical fans widely use "Album" for the opus because it's a tag that practically every music-playing device supports.
I advocate using tags instead of file structure for searching/cataloging/organizing because tags are self-contained, portable, and universal, and not dependent on any particular OS or platform, NOT because I think tags are very well-designed.
And FWIW I almost
never use the tags from any of the online databases - I hand edit all my own tags for accuracy, completeness, and consistency. It's more work but you only have to do it once.