Original version of the music video, "Arthur & Guinevere" - an angst-y look at their story from Season One through Season Three's, The Changeling.
Arthur & Guinevere - music video by AudiRox
Note: Unfortunately, the video is blocked from these countries: Argentina, Austria, Belgium, Chile, Colombia, Denmark, Finland, Germany, Greece, Hungary, Malaysia, Norway, Peru, Philippines, Poland, Portugal, Romania, Russia, Saudi Arabia, Singapore, Sweden, Switzerland, Thailand, Venezuela. =(
There doesn't seem to be a "fanwork: video" tag? Or am I just not looking hard enough?