I'd suggest Chuck Palahniuk. Choke is my favorite, but Fight Club, Snuff, Lullaby, Haunted...they're all pretty good.
How about zombies? World War Z or The Zombie Survival Guide by Max Brooks. The Living Dead edited by John Joseph Adams is all zombie short stories.
The Stand by Stephen King...classic post-apocalyptic fiction. Maybe A Canticle for Leibowitz by Arthur Miller, also post-apocalyptic, but unique. If you're in the mood for short stories, maybe Wastelands edited by John Joseph Adams, more stories of the apocalypse. One Second After by William Forstchen, very realistic threat, and very realistic aftermath...really a good read.
War fiction? Birdsong by Sebastian Faulks..a few intense sex scenes but REALLY good war scenes. The Things They Carried by Tim O'Brien, A Rumor of War by Phillip Caputo, Going After Cacciato by Tim O'Brien..
You didn't say no fantasy...so maybe The Shadow of the Wind by Carlos Ruiz Zafon (fantastic book!), His Majesty's Dragon by Naomi Novik, The Dark Tower by Stephen King.
Non-fiction? The Lost City of Z by David Grann (search for El Dorado), Stiff by Mary Roach (the life of a cadaver), The Radioactive Boy Scout by Ken Silverstein (eagle scout built a nuclear reactor in his backyard).
Just regular fiction, not really genre specific. Atonement by Ian McEwan (haven't been disappointed in any of his books), The Wasp Factory by Iain Banks (he normally writes science fiction, but this one more on the horror side...a few gruesome scenes that have stuck with me), Cotton Malone series by Steve Berry (action adventure, history, treasure hunt, starts with The Templar Legacy).