I recently saw some discussion on the Griffin PowerMate, a USB connected volume knob, and it's use with GIMP.   I've been trying to understand exactly why this would be useful.  While it's possible to map the features of the knob to various functions in the GIMP, it would require yet another change in manual device management.  Any feature this device can be mapped to can also be mapped to, for example, some function on a drawing tablet.  Or a mouse cliek.  Or a mouse click combined with a keyboard meta key.  In other words, I can do the same thing with fewer devices.  So why exactly would I need this additional device?

I think the knob is kinda cool, mind you.  I can imagine using it for zooming or panning features in large images without having to use the Navigator preview.  But I'm not sure it's worth cluttering my desk with yet another device for something I can already do with the devices I have.

If you can think of some reason why this device would be a benefit for gimp users, let me know and I'll post it here. 

For those who take the plunge with this device and want to have it auto-detected, take a look at the Gentoo Howto for configuring UDEV to recognize it under a 2.6 kernel.