Wow, the things in this thread that people don't know that windows CAN ALREADY DO.
Sure - they aren't the default, but they can be done in Windows, some of them since Win98.
Hint: You can add as many other power plans as you like, and they will show up on the taskbar power plan menu. I have four on my brand new laptop that I just got last week. I created the other two for gaming (Max everything, even more than the default High Performance) and another very low power, long battery life use.