JuiceDefender is the solution: it greatly improves battery life by intelligently and transparently managing for you mobile connectivity and other battery-sensitive components, disabling them when you don’t actually need them.
SeePU gives you constant, second-by-second awareness of CPU, RAM and network usage - always under control via animated icons in the notification area. It can also show historical usage graphs in the notification pane, and allows you to kill with one tap that pesky app that’s stuck at 100% CPU usage.
JuicePlotter collects and plots screen brightness, radio usage, charging status and battery temperature - either in one elegant, colour-coded graph or in separate stacked ones.
It lets you easily analyze battery performance on a day-by-day basis, and it has a widget that shows an accurate estimate of how long it will take to fully discharge/recharge your battery.
JuiceDefender beta builds are available on the Market!