I specifically love Dies the Fire (and the ensuing novels) by S.M. Stirling. Don't always love his characters, but that sense of pulling together and rebuilding a society after a massive societal upheaval is something I can't stop thinking about. Especially from the variety of perspectives and styles of the different groups that form within that story. I've also read One Second After, by William Forstchen. And I want to be clear that I truly hate that book for a ton of reasons (you can find multiple posts and comments about it in my post history) but the story is not one of them and was in fact compelling enough that I powered through my hatred to finish it.
I have recently tried reading Earth Abides - that was not it for me. Not because of the story, but because I couldn't stand Ish.
Thanks in advance!