If Linux is your primary on-the-go computer OS, you'll find that it's really versatile in handling power consumption — if you know how to get around its settings. A poster at the Productive Geek forums shows us some power-saving setups.
Most Linux distributions, including Ubuntu, have their own Power Management configuration tools for handling the basics of screen dimming, hard drive spinning, and other basics. But for managing your CPU scaling, and keeping your system from spending too much time writing file access details, you'll want to read up on how to install things like relatime, and fine-tune the splitting of CPU load between multiple processors. Hit the link for a full run-down.
How to Maximize the Battery Life on Your Linux Laptop [Productive Geek]