I've set up my posedirectory as follows:
materials characters, with subdirectories for V2, V3 etc.
materials creatures
materials clothing, again with subdirectories
materials hair
materials architecture
materials environment
materials various, for all the other stuff with materialsettings
poses:
subdirectries for V2, V3 etc.
subdirectory creature poses
subdirectory props poses

This covers 99% of all things (at least for me) and what doesn't fit in one af these directories, well just remember where you've put it. This set up requires that you manually put the right files in the right directory and that takes some time but it will save you a lot of time when you're searching for that one particular posefile.