While the directory listing of Fuppes is a very nice feature, most other uPnP/DLNA media servers offer the ability to browse your media library independent of the file structure and by Id3-tags instead. This would make a very nice addition to fuppes.
For example (main menu):
I have not yet found a media server that can handle my mp3-collection (around 26 000 songs, in around 15 000 directories) and provide the interface listed above. Fuppes seems to handle the collection very well though, which is why it's my media server of choice right now. Browsing the directory structure to find playlists and individual songs is quite bothersome though, especially since my DLNA-client has a very sluggish interface.
Using playlists is the most convenient way to handle such a large collection, at least in my mind. However, often they are located deep within the directory tree. Having playlists listed separately in the main menu would make my life so much simpler.