Kyle at 2011-10-18 17:39:39:
We recently had a big power outage in San Diego and it was fun to see everyone freak out. Even though it only lasted the night, it was interesting to see how thin society and order really are and how easily it can be stripped away.
Not a movie, but The Walking Dead fits into this category.
And it probably doesn't completely fall into this category but when you said "post-apocalypse stories raise another issue: Who would I be?" it made me think of Saving Private Ryan and the bets the soldiers take as to the profession of Tom Hanks' character. All we know him as is the tough nosed war hero, but back home before the war he was just a school teacher. So maybe living in the midst of WWII as a soldier is similar to living in a post apocalyptic world.