In my opinion it's made people feel safer where as they are not, just because he is gone al queda isn't going to fall apart. They will continue doing what they do. Also I think there is almost definatley going to be a retaliation of some sort soon.
I've read a thread over on airliners.net where people think security will be stepped down on planes, most of the replies show how it's been increased and I have to agree in most places security will be stepped up. But only time will tell I suppose!