I am firmly of the opinion that this is one of the top 5 books ever written by humankind. I first read it my senior year in high school and have tried to read it every spring since. Some years I never got around to it, but I still have a pretty good record over these last 17 years.
Possibly the finest closing line in literature. Say what you will about Hemingway, I think he can rest his reputation on that one sentence.
I'll also second the praise for "Founding Brothers." What a great read -- really humanizes the founders.