I love A Canticle for Leibowitz: it's amazing, a real mind-bender. Neomedievalist SF/postapocalypse/dystopia is one of my favourite sub-genres, including The Handmaid's Tale, Russel Hoban's Riddley Walker, Will Self's The Book of Dave, Brian Aldiss' Greybeard, and at a stretch, McCarthy's The Road.

I didn't like the Children of Men book, I found the film a lot better. But I liked Aldiss' Greybeard: he was there first (1964) with the no kids being born idea.

I currently have lined up to read: Daniel Wilson's Robopocalypse, Ian McDonald's Brasyl, Rob Ziegler's Seed (eco-SF), China Mieville's Embassytown, and want to check out Kameron Hurley's God's War. So much SF, so little time.