But if I had to pick one it would be BiaB. I am playing in genres I never would be playing in if it wasn't for BiaB. Also the melodist and soloist can generate phrases that can lead to entire songs.
Mario - same here. I suspect its the case for others as well. In my case, these can sometimes be 'unplanned inspirations'. BIAB exposes me to styles that I would never think of, and elements of these give me ideas that lead to a full song also. As for #17, I reckon a Bailey's Irish Cream or a nice tawny port would surely help my creativity!