I just purchased a new iPhone 5 64Gb model and my current network is 3G only. I have done nothing besides add music to it. I turned off bluetooth, turned off location services and turned the brightness to minimum with a 1 minute lock. The battery drains 7% in the first hour that it is unplugged. Don't quote me on it, but according to my math that would mean that the battery will only last 14 hours. I have serious doubts that this is in line with the advertised standard at http://www.apple.com/iphone/specs.html
What's the point of having an iPhone if you have to constantly gimp it by turning off all of the services? This is my first mobile device from Apple and I am NOT HAPPY at all.