Those of us who drive laptops are usually more aware of power management than the desktop jockeys. When you're running on battery power only, you want to have your laptop running as efficiently as possible. In Vista, you can optimize settings to conserve energy, go for flat out performance or achieve some kind of sensible balance between the two.
Activating power management is simple, and you have two paths to take you there. If you like living in the past and have set Control Panel to Classic View, simply open the Control Panel and then open the Power Options icon. If you're more up-to-date, open Control Panel, then System and Maintenance, then select Power Options. Either way you're looking at very similar screens.
Vista gives you a web-like interface that's easier to use than the usual tabbed dialog boxes in XP. You have three power plans to work with, and if your PC is a desktop the right column will read "Energy Savings". You don't have any head scratching involved to determine what each selection controls.
The first selection, Balanced power provides total performance when you need it while saving power during idle periods. The Power saver option reduces system performance to give laptop users maximum battery life. High performance does exactly what it says, but don't expect to be able to watch the Lord of the Rings trilogy on your laptop on battery power.
Examine the dialog box and you will notice that each of the power plans has a Change plan settings link. Any of these will take you to another dialog box where you can change the default settings. The defaults are reasonable and make sense. Change them if you must, but not because you can.
You can refine your setting further by selecting the Change Advanced Power Settings link. The number of power setting adjustments you can make to your computer in this dialog box is nothing short of mind boggling. You can regulate power consumption for USB devices, hard disks, displays, and even wireless devices. It's easy to get carried away.