The Aeneid, if you're up for some serious metaphor-chewing.
The Road by Cormac McCarthy - a really good post-apocalyptic novel.
Dune by Frank Herbert; hurray for sci-fi!
Do Androids Dream of Electric Sheep? by Philip K Dick.....again, three cheers for sci-fi! (
and it's a mind-blowing read)
For non-fiction, I'd say War by Gwynne Dyer. Very interesting read (oh, and anything by Jared Diamond as well. Collapse and Guns, Germs and Steel are quite good)