Not religions but Islam will if things keep going the way they are.

Religion would be fine if people practiced it among themselves helping to better each other, but it always ends up turning cancerous. Mainly, because it devolves into a power struggle with people who want to turn what they believe into the status quo. You end up getting people that don't fear death because you can put anything in their heads.

But, if it weren't religion, it would be something else humanity would battle over. In the end, it's mankind's greatest flaw. The need for conflict and animosity, even when knowing how the outcome would hurt them.

Namely, if you outlaw religion, something will just take its place.

Banning the religion(s) will simply attract more terrorists.

Surveillance won't do much either. Most of these terrorists are already on the watch list and are typically booted out from their mosques/churches/whatever. With so many people on this planet, we will experience such attacks. Yes, it's an awful thing to say, but what else should we do? Lie and try to come up with some "revolutionary" idea to magically make terrorism disappear?

Banning religion in regions where extremism is generally a much smaller issue won't do much on a global scale. Not to mention the immense hostility an outright ban on religion would arouse from extremists across the globe. It's more likely to make things worse.
Allowing or not allowing religion won't have much of an impact; not starting or escalating huge armed conflicts that ruin entire regions and nations and throw vast populations into a state of poverty and despair which leads to simpler recruitment of terrorists will have a much bigger impact.

In short; disallowing a certain behavior is highly inefficient, managing what causes the behavior to begin with is not.

Hmm, I don't think so. Most people might know me here as a socialist, but I'm also a catholic at heart. Religion is very much ingrained in Europe, just not as obvious as it was before. There are still a great amount of young people who are religious and while some people might jump at the opportunity to push religion out of the public sphere, it will be very difficult.

Banning religion would probably be impossible, but taking it out of the public eye would be nice.

I doubt it would have any affect on terrorism, as I'm pretty sure terrorism is already banned but that doesn't seem to stop them.
Getting rid of some stupid religious laws and taxing churches and mosques etc would be a great start though. I feel we need that terrorism or no terrorism.

Naturally we'll eventually have a future without fairy tails that people believe in.

Ban religion in the Western World?

Lawl. Few things would be less "western", that would be a huge step back for the human race and for western ideals in general. We can't break down and ban things every time something terrible happens, as if we did we'd have gotten rid of cars long ago that kill over a million people every year.

There is no way to remove "threat" from life. Overreacting will only make things worse.

What? No way. Remember when that one muslim guy prayed for the victims of a terrorist attack and reached the news for it? The Islam will be OBLIGATORY

If it's not killing for religious beliefs, then it will be killing for which is the better gaming console.

Absolutelly. It is just a matter of time till staged false flag events are used to propagate the idea that not only muslins, but also christians are very dangerous
It is a matter of years till religion becomes regulated in paper form, and very real violence will rise from the prohibitions.
In the case of christians, this will generate chaos, cause we have a spiritual mandate of confessing Christ every single day and occasion we get, and never ever deny Him or our faith.
That will cause massive prisons and other punishments, all around the world.
In the long run, the "solution" provided by all the states will be a pasteurized, all compassing, world religion, a amalgama of various faiths and beliefs. And, to better enforce such a thing, and to prevent terrorist funds to flow, a world government and a world currency will be created.
To those that fail to comply, death penalty, maybe even guillotines.
How long could this take?
If things keep at this pace, 15, 20, maybe 30 years at the most.
But, as with everything, it could slow down once again and lose steam.
We will see.