It is easy to stand back at 100ft and say this type of crap, but the fact is, crazy people are all around us, and we should try to be proactive instead of reactive.
We as a society owe it ourselves to reflect on events such as this, and see if there was anything that could have been done to prevent it. If the answer is yes, then we SHOULD act. Does that mean freedoms need to be restricted, laws to be enacted? No, it could mean better technology, maybe better security, maybe MORE security.
I hope no new laws come of something like this, but if it means reducing the chance that this happens again, I am all for it.
Our rights are absolute, but we also need to compromise. We can't let ourselves become 1984, but we can become safer, smarter, more efficient with regards to security.