Taylor: gnome-battery-bench
On his blog, Owen Taylor introduces gnome-battery-bench, which is a tool to measure power usage that should help lengthen battery life on Linux systems. It can smooth out the somewhat jumpy numbers reported by powertop and provide graphical feedback of parameters like power usage and estimated battery life remaining.
"gnome-battery-bench is designed as a graphical application because I want to encourage people to explore with it and find out interactively what is using power on their system. And graphing is also useful so that the user can see when something is going wrong with the measurement; sometimes batteries will report data that jumps around. But there’s also a command line version that can be used for automatic scripting of benchmarks.

I decided to use recorded sequences of events for a couple of reasons: first, it’s easy for anybody to create new test sequences – you just run the gnome-battery-bench command line tool in record mode and do what you want to test. Second, playing back event sequences at a low level simulates user interaction very accurately. There is little CPU overhead, and as far as the desktop is concerned it’s exactly like user input."