Right, I've made a couple of early posts on this, and have read pretty much all of the others.
My personal summary is as follows.
1. Nothing much will change until religious extremists cease to exist - I don't know of any acts of terrorism committed by aethists.
2. Religious extremism is a product of ignorance (we could argue that all religious belief is a product of ignorance, very few educated people hold strong religious beliefs, if any) but it will take a very long time indeed before improved education wipes out religious extremism, which relies on ignorance and lack of logic.
3. It is impossible to guard people (either generally or to guard individuals) against extremist attacks. Having an armed police guard at the offices proves that, and it hasn't worked in other situations either. And having large numbers or armed police or military on the streets is just another token effort, nothing more than reassurance to the public - I saw a bit on the TV yesterday, showing a soldier in Paris, standing around with nothing more than an ancient bolt action rifle
4. It is literally impossible to stop terrorists getting weapons to use in these atrocities. These particular terrorists were armed with AK74 assault weapons (wrongly described in the media as AK47's) and a RPG, even if armed police had been available, they would stood no real chance. Much more COULD be done, but if the French government is anything like our own, nothing WILL be done because it would involve spending real money - thousands of containers containing fresh produce arrive here every week in containers, and Customs doesn't have the resources to check their contents.
5. Governments need to spend much more on their intelligence services, they need to have the resources necessary to monitor suspected terrorists ACTIVELY. Stopping something from happening is far more effective than shooting the criminals after it's happened.
6. More effective government action must be balanced against human rights i.e. have the laws in place, have the infrastructure and resources in place, but use these powers, don't abuse them - abusing them is not only wrong, but also tends to recruit new people to extremism.