Recently, I read great books : the Millenium trilogy (for english natives : "The Girl with the Dragon Tattoo" and "The Girl Who Played with Fire", the third book is not out yet, I guess). It's a very special thriller, totally different from anything I ever read. It's 1800 pages long, but you almost cannot put it down once you started it. Steig Larson, the author, died soon after he finished the third book, just before they all were supposed to be published. If you have to flight for more than 6 hours, definitively a must have !
The second book is a bit different : "Jesus sans Jesus" (ie, Jesus without Jesus ). Basically, it's the history of the christian church first days. It could have been named "Building a religion for dummies". Religion put aside, it just demonstrates how the roman empire adopted the christian religion in 3 centuries, and how it transformed the empire from inside out. Way better than "God Delusion" from Richard Dawkins (I find this book a bit too messy.)