Not looking forward to doing it myself, but have to get around to it one of these days.
Thinking it'll start with dividing in to genres. Probably place genres together in case I want to change it up a little (hip-hop near drum'n'bass; dub step near techno near tech-house near house).
Inside a genre I'll group them by label, and then by catalogue number (saves having to try and figure out release date). Probably order the label groups by name rather than style: gets a little diverse sometimes...