Two nice things about my setup, one being I can simply middle-click the taskbar and mute the volume.
The other is I can simply move the mouse over any spot on the taskbar, and scroll the mouse wheel to quickly lower and raise the volume.
Quick, convenient and responsive.
The volume slider is performed via a tiny app called VoluMouse. http://www.snapfiles.com/reviews/Volumouse/volumouse.html
The following is the registry configuration file "volumouse.reg":
Windows Registry Editor Version 5.00
When you stick the program in your startup menu, just use the "/nodlg" switch to avoid the initial dialogue display.
Mute is performed via the Macro Express program. http://www.macroexpress.com/
This is the script used to achieve this:
Under Properties -> Activation just set activation to Middle Mouse click. Can isolate to height/width of taskbar but probably doesn't matter.
For Properties -> Scope, set it to the Explorer.Exe program.