If you're looking at Android OS in the Settings => Battery stats, don't forget to do a refresh every few minutes. Keep in mind this is a cumulative percentage of total usage, so the values aren't relative until you start looking at them over a period of time. Just glancing at these numbers for a moment does not give you a clear picture of how to set your power. Also, while studying these cumulative values and doing refreshes every once in a while, notice how small an amount of difference CPU usage actually makes in the total picture of your power usage, especially with well tuned kernels (ie: Chevy's, etc.). If you really want to improve things with battery usage, there are other usage areas that make more sense to worry about... For example, while personally I love live wallpapers (Aquarium is my favorite), next to the radios, they are probably the biggest optional culprit of battery usage and heat.