For militant and extremist groups, defeat is disastrous, and this is an enormous defeat for Al Qaeda. The group's political fortunes were moribund following the rapid overthrow of the Taliban in Afghanistan, and were revived only by the ill-considered invasion of Iraq, which gave it a new battleground, rationalization and lease on life for a number of years.
The loss of this vital symbolic figure, no matter how impotent he had become in reality, will undoubtedly be another significant blow to Salafist-Jihadist ideology. They may have gained a martyr, but they've lost the image of a defiant leader able to combat the Soviet Union and America alike with impunity. His deputy, the Egyptian fanatic Ayman Zawahiri, lacks the charismatic appeal bin Laden had among certain extremists, and he has no apparent successor.
You'll never hear the whirring sound of a projector again.