It's an old one, but Roadside Picnic and its loose movie adaptation STALKER are both very good. Not quite a "true" post-apoc as it'd be today, in that The Zone is a small place in a "normal" world that the protagonists choose to enter, but they certainly confront the ending of "what came before" through an Event of sudden and total alienation.

The Earth Abides is also good, a very early story about the aftermath of a superplague. Life goes on, and humans remain human.