One thing that has always bothered me about this tragedy is the fact how little has been done since. If you look at it- without the terrorism aspect- you can see that a problem existed in any case. Any city that can afford to build structures of that size can afford to maintain a fire fighting force capable of protecting it. The firefighters who gave their lives that day would probably agree with me too.
I think the city of New York- and any city with skyscrapers- should have to invest in helicopter mounted firefighting equipment. It necessarily take a terrorist attack to create another such disaster.