I always like ncurses frontends. They probably shouldn't be the only frontends, but the fact that they exist show the flexibility of the library, and allow for more flexibility as well (say, you have a server box that has a MIDI port, and it's the only box around that has one; it would be a shame to be required to install X just to make use of it).
For similar reasons I have made CLArcomage, the command-line frontend to libarcomage, the Arcomage (card game) library I wrote. It's probably not used much, but it's cool and of educational value to have it available. The whole thing only takes a bit over 100 lines of code, so why not? It's also great for debugging the library (when you're not sure if the bug is in the library or the frontend).