First of all, I know that this can kind of be achieved through using the "Track Browser", but I don't really use the track browser and would like to see this as an alternative.
My suggestion is that, in the "Left Navigation Panel", where the user sees "Library", "Playlists", "Internet", "Computer" (and so), it should be possible to add a few more things, such as "Moods", "Occasions", "Tempo", "Genres" and maybe even other properties that I can't come up with now.
The user should be able to show or hide these under Preference -> Layout, just like it works now with the previously mentioned "navigation tabs".
Then it could look something like this:
> Library
> Playlists
> Moods
> Occasions
> Tempo
> Internet
> Computer
and within each "navigation tab", the sub-categories should be set based on how they have been set for different songs through the music library. So, for example, if I have set mood "Calm" for one song, and mood "Happy" for another these two moods would show up here, and clicking on them would show me the songs in question. Same obviously goes for the other suggested "navigation tabs".
Currently, I'm achieving this by creating automated playlists for these things. The problem with that is every playlist for every mood, occasion, tempo etcetera must be created manually whereas my suggestion would just do that automatically from the properties set throughout the music library.
Thanks.