I highly recommend the book "Making Software: What Really Works, and Why We Believe It". It's a collection of essays showing statistical studies on certain software techniques.
100% agree. So many blogs and books talk about how X is better than Y, or how Z is bad, but it is usually just a gut feeling with very little data to back it up. This book on the other hand is chock full of actual data on many topics that are debated all of the time. If you only read one programming book this decade make it this one. For me it replaces mythical man month as one of those books I now expect others have read if they want to debate the topics it presents.
