Push button with a click on capability is the most versitile. No exposed wires, ability to turn and leave light on without needing to hold the button, in case you need to use that hand for something else, or need to have the light on for extended periods of time. Surefire makes a switch that has all of these options. It is expensive, but it is the most versitile option available. Its called the XM tail cap. It has a removable pressure pad so you can add it if you want or remove it if you dont. It also has a push button with a click on/off capability.