I never thought that I would recommend a book before I finished it, but here I am, less than 1/8th of the way through Neal Stephenson's latest, and shouting to anyone who will listen that it is a must read.
Those who have read his previous works know Stephenson has a knack for portraying remarkably intelligent people doing not-so-intelligent things in bizarre situations, and he does it while keeping his people in character and making the bizarre situations totally believable.
His best books (Cryptonomicon and the System of the World trilogy for example) tend to run well over a thousand pages without an unnecessary word, and Reamde is no exception.
I would write more, but I can't wait to get back to the book.