Some great reads listed here. Adding a few not yet mentioned, categorized by genre:
history
World War One: A Short History, by Norman Stone
Brief, highly readable and an insightful analysis of politics, strategy, colonialism, industrialism and economics.
The Fog of War: Lessons from the Life of Robert S. McNamara, James G. Blight and Janet M. Lang
Not quite an apologist's treatment, more an insider's look that reaches back to WWII with astounding information.
Wartime: Understanding and Behavior in the Second World War by Paul Fussell
"part memoir, part cultural-critical study, and that is essential reading for anyone interested in the history of conflict"
nonfiction
Class: A Guide Through the American Status System, by Paul Fussell
"explodes the sacred American myth of social equality with eagle-eyed irreverence and iconoclastic wit"
The Natural History of the Rich: a Field Guide, by Richard Conniff
Compares the superrich to various members of the animal kingdom. Prepare to laugh out loud.
biography / memoir
The Life and Times of the Thunderbolt Kid: A Memoir by Bill Bryson
Hilarious, most appealing to those born in 50's and early 60's.
Highcastle by Stanislaw Lem
Another look at growing up, this time as a child in prewar and wartime Poland by the renowned science fiction author.
science
The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements, by Sam Kean
A fascinating look at the periodic table. A great read with footnotes that are as interesting and entertaining as the text itself.
science fiction
Anything by Stanislaw Lem, but especially The Star Diaries, Solaris and The Futurological Congress. Lem also wrote more 'straight' scifi as well as fantasies and fables, book reviews of and forewords for non-existent books, among other things.
other
The Hamptons Dictionary by Miles Jaffe
"A Devil's Dictionary for the modern age, The Hamptons Dictionary is a wicked social satire and hysterical lexical send-up of the rich and famous who flock to the Hamptons each summer and the locals who count the minutes until Labor Day when they leave."
One Human Minute by Stanislaw Lem
"purports to be a review of a book collecting statistics on everything that occurs on Earth in 60 seconds; in fact, it's a meditation on the nature of reality and the meaning of human behaviorplus a wickedly funny satire of publishing."