Quick switching default audio device

I have 5.1 headphones on my SB Live! 5.1 and a stereo headset on my AC97. I want a quick way to switch either everything or audio of choice (at least game audio, voice audio can stay on the headset) between the audio devices. The quickest way I know of is to right click the system tray icon and go through the Audio Properties, but I want to be able to do it easily within about 5 seconds probably using various custom configurations and a system tray dialog, and hotkeys would be nice so I don't need to leave my game to switch it.

Does anyone know of software (especially freeware) that'll do this or something similar?