I'm a huge fan of post-apocalyptic novels. End of civilization, everyone dead, cities crumbling, a few scavengers all that's left of humanity. I like the low-brow stuff with mutants and gore, and I like the middle-brow stuff with reflections on humanity.
What I love is the melancholy tone of the loss of civilization. At first it's fat city, free food and cars and everything for the taking. But things slowly deteriorate: the power, the water, the cars. With less than 100 survivors in the whole Bay Area creating a society is tough, and reviving the trappings of civilization is impossible.
The second half of the book is even sadder. The protagonist sets himself up as the leader of a small group of people and sets to having children. All well and good, but he's the only intellectual of the bunch. He valiantly tries to teach kids to read, preserves a library for them, tries to show them how technology works and what their heritage was. But it's a failure and the new society reverts back to simple hunting and superstition. All of our hero's knowledge is useless.
I love the idea of the impermanence of civilization; Earth Abides describes it very well.