I suspect the biggest impact will be in America itself. Bin Laden was beginning to fade across most of the middle east, al-qaeda influence was becoming more restricted to already unstable areas such as Somalia or Yemen and a heartland around Pakistan and Afghanistan. I'd expect some revenge attacks, but this will overall continue the weakening of the Al-Qaeda movement.
But as I say, it's the US that will feel this most. The fact that so many families will now feel justice has been done, and probably most importantly the fact that this is probably a more powerful and effective display of American intelligence and military capability than Rumsfeld ever managed. Obama seems to have borne himself very well throughout, as well, and clearly personally has been pursuing this goal, so I'd be surprised if this didn't reflect well on him in the polls.
Pakistan has big, big questions to answer about why he was found 700m away from a major military academy though - and there are still worries that the anger at an operation which (while extremely successful) violated Pakistani sovereignty could lead to a backlash.
