The most fun I ever had with an essay was when I was studying film at Sheffield Uni, and the question was this:
"Pick a quote explaining the meaning of cinema from one of the recognised pioneers in the field and argue for or against that meaning."
I picked this quote (parphrasing) by Jean Luc Godard
Cinema is not the reflection of reality, but the reality of the reflection.
You really can't go wrong after that one, whatever you write is going to be arguably correct.