Vista is first OS that gets very customizable Volume Mixer for running programs. To see it in action,
2. Volume Mixer window will open up and show the running applications and it’s volume level. You can change the settings just the way you want.
How cool is that? My radio broadcast is set to low, but my messenger alerts are set to high.
There is some issue for some users about the Volume Mixer window refresh issues: See the Microsoft Knowledge base article: The volume slider may appear with a black background in Volume Mixer in Windows Vista