The list of APIs new to Windows 7, and all the other (previously released) API functions can be found right here:

Functions by Release (MSDN Library)

The PowerSetRequest / PowerRequestAwayModeRequired mode looks particularly interesting.  It seems to be a new power saving mode:

The system enters away mode instead of sleep in response to explicit action by the user. In away mode, the system continues to run but turns off audio and video to give the appearance of sleep.