30 Day SF & Fantasy Challenge Day 18: Best Post-Apocalyptic Story

The realm of science fiction is great for dealing with end-of-the-world storylines as it takes us past the events of the apocalypse. What we want to know today are which stories do this best in your medium(s) of choice. This is fertile ground for science fiction but we also get this in a number of fantasy storylines as well with the world in ruin and trying to maintain some sort of civilization.

Bonus Question: Which series do you think did this the worst or most unrealistic?