Oh man, I could have really used something like this 4 years ago. I was doing a personal project that would have involved a node graph UI, and it was actually kind of challenging finding an existing library this simple and nice looking. Yeah, I know there's D3.js but that involved way more knowledge and learning than I was interested in. If I remember correctly, I ended up writing my own.

Dunno if it's feasible with the way it's designed, but it'd be really useful for this to have force-directed drawing, even if it's not a real-time thing.