I think it would be really neat to connect Fitbit and Spotify. That way, when I am listening to an audiobook, or anything, on Spotify as I'm going to sleep, there will be a note of where I was in my audiobook when I fell asleep. I know Fitbit doesn't track sleep under an hour but it will tell you what time you went to sleep once you sleep for more than an hour. So while it would be most ideal for the audiobook/music to stop playing as soon you fall asleep, the way that Fitbit works, the next best thing would be to note what time in a track I was in so I don't have to search what I last remember hearing of the story.
Also if I could look at my Fitbit to see what song is playing that would be cool.