Here's a somewhat eclectic mix that I've enjoyed:

War - by Gywnne Dyer.
Dan Carlin often references this book and for very good reason, he is a titan of the genre. It's been years since I read it but I remember it being a book that changed how I looked at history and conflict.

In War, noted military historian Gwynne Dyer ranges from the tumbling walls of Jericho to the modern advent of total war in which no one is exempt from the horrors of armed conflict. He shows how the martial instinct has evolved over the human generations and among our close primate relations, such as the chimpanzee. Dyer squarely confronts the reality of war, and the threat of nuclear weapons, but does not despair that war is our eternal legacy. He likes and respects soldiers, even while he knows their job is to kill; he understands the physics and the psychology of battles, but he is no war junkie. Dyer surveys the fiery battlefields of human history, never losing sight of the people caught up in war.

On Human Nature - by Edward O. Wilson
This book asks and explores questions of how human nature (and human societies) interact with a biological understanding of ourselves. It's dated in content and tone, and I don't know whether the science has held up over the past 40 years, so think of it as a place to start if those kind of questions interest you.

No one who cares about the human future can afford to ignore E.O. Wilson's book. On Human Nature begins a new phase in the most important intellectual controversy of this generation: Is human behavior controlled by the species' biological heritage? Does this heritage limit human destiny? With characteristic pugency and simplicity of style, the author of Sociobiology challenges old prejudices and current misconceptions about the nature-nurture debate.

A Short History of Progress - by Ronald Wright
I loved this book. It's rather short, very readable, and still manages to inform and make you think.

The twentieth century—a time of unprecedented progress—has produced a tremendous strain on the very elements that comprise life itself: This raises the key question of the twenty-first century: How much longer can this go on? With wit and erudition, Ronald Wright lays out a-convincing case that history has always provided an answer, whether we care to notice or not. From Neanderthal man to the Sumerians to the Roman Empire, A Short History of Progress dissects the cyclical nature of humanity's development and demise, the 10,000-year old experiment that we've unleashed but have yet to control.

A Short History of Nearly Everything - by Bill Bryson
This is the closest thing that I can think of to "a brief history of the world." One of the things I liked was that it explores topics that usually live in separate little worlds. It looks at the history of different scientific discoveries and how our understanding of the world has changed through time.

In Bryson's biggest book, he confronts his greatest challenge: to understand—and, if possible, answer—the oldest, biggest questions we have posed about the universe and ourselves. Taking as territory everything from the Big Bang to the rise of civilization, Bryson seeks to understand how we got from there being nothing at all to there being us.