just read Blindsight by Peter Watts

Figured I should give honorable mention to my actual two favorites, The Gunslinger (and the rest of Dark Tower) and The Stand both by Stephen King. Just really really great worldbuilding and I love apocalyptic fiction. Also the Passage series is great because when the whole vampire apocalypse is finally resolved society at large doesn't just go back to rebuilding the preapocalypse status quo but is fundamentally changed in profound and differing ways around the whole world.