"Worldviews - An Introduction to the History and Philosophy of Science" by Richard DeWitt. Instead of doing a history-only or philosophy-only take on the topic, I really enjoyed how DeWitt meshed these two viewpoints and examined how they inter-played with each other. It overthrew forever my image of the ancients as a group of irrational, superstitious people who believed in such funny notions as the Sun and the planets orbiting the Earth. DeWitt nicely explains how given the data that they had, their conclusions were very much rational. For example, it's very difficult to imagine from our everyday experience that earth could be orbiting the Sun at a speed of some 30 km/sec.
"A History of the World" by Andrew Marr. I find history a simultaneously fascinating and frustrating subject. Fascinating, because a good knowledge of history makes the present day world seem a lot more meaningful and un-arbitrary. Frustrating, because it's difficult to find a history book that's not just a list of facts and dates. Marr's work walks us through history via vivid portrayals of interesting personalities and events. I found the accompanying documentary series equally interesting as well.
"The Philosophy of Cognitive Behavioural Therapy: Stoic Philosophy as Rational and Cognitive Psychotherapy" by Donald Robertson. This book examines the common grounds between stoic (and to far lesser extent, Buddhist) philosophies and modern cognitive behavioral therapy. It also lists some of the tools in the stoic's tool-chest to tackle common anxieties and worries about life. The nice thing about this book is that it teaches you to treat philosophy as a method of self-therapy, which immediately opens up an ancient fund of literature to tackle day to day problems.