Daniel Ray- The Killer Angels
I chose The Killer Angels because I've always been interested in the Civil War, and my brother already had a copy laying around from when he read it.  I like the book gets into the different commanders' minds, portraying what they're thinking as they watched the fighting.  I also think it's good to have a perspective on the battle from the Southern commanders.  History is often written by the winners, but this book looks at it from the perspective of the losers.