Personally I use VolumeTray, an excellent little program that sits in your Taskbar.
It provides two options for changing volume:
1. Custombisable hotkeys
2. Left click on the taskbar icon = volume up
Right click on the taksbar icon = volume down
By default it puts two icons on the taskbar, which is a bit of overkill, but it can be very easily customised in user preferences to use just one.
Grab it from http://glorysoft.omsk.ru/