This actually reminds me of a couple of books I left off the list. Essentially, any of my teaching books by Kelly Gallagher (i.e. Write Like This). These were assigned/suggested to me by my favorite professor and they have really informed my ideas when it comes to teaching.
On a different but sort of similar note, my book of ee cummings poetry, XAIPE, and also his play, Santa Claus: A Morality. Outside of the fact that I think ee cummings is a genius and my favorite poet, it was his poetry and this play that got me into more academic writing. I was going to do a big paper on ee cummings for my English Capstone, but I dropped my English major. I'm still planning on writing that paper just for fun though.