energy efficient default user settings

The cost of the energy will increase in the coming years, what ever the primary source is. Morerover each primary source of the electricity has drawbacks. However, many default user settings are set to arbitrary values which waste energy without technical reasons.

For example, the default screen sleep time-out is set to 30 minutes when operating on mains. The default screen saver is sometimes set to a 3D intensive application by default.

All those default settings have the below drawbacks :
- it wastes a lot of energy (if you think about the number of computers running Ubuntu)
- it creates heat (drawbacks if your room is hot)
- a laptop will possibly require more time in order to recharge its batteries
- ...