I have gotten into Post-Apocalyptic books lately for some reason, so:
Any of the "Silo" books by Hugh Howey ("Wool", "Shift" and "Dust")
The Silo stories seem to be so good that other authors are now writing "Silo" books that build on Howey's books...
And this is the best zombie book I've ever read:
Amazon.com: Apocalypse Z: The Beginning of the End eBook: Manel Loureiro, Pamela Carmell: Kindle Store