I end up summarising what I've written, and then, if possible, I give a sentence explaining the net result of what I have proven. So for instance, in my last essay about "language is deeply personal and yet through it, we expose our allegiances, desires, beliefs and much more", I concluded by saying that it was precisely the personal nature of language than is able to reveal so much about an individual. Admittedly, for some essays I tend to parrot my intros.
Systematically listing your arguments...not explicitly. You can make mention to them, certainly, but don't provide a list like "firstly, secondly, thirdly" etc. Really, you want to conclude by communicating to the reader that you have said something of substance, of meaning, and that the reader can take something away from your essay.
Just my two cents.