The Wahhabists spreading their ideology is a problem. But on a purely statistical basis in Canada, I (particularly as VisMin) need to fear young white guys. They are more like to shoot up a mosque (Quebec City) or run over a family out for a walk (London) than a Muslim in Canada successfully executing a terrorist attack (Parliament Hill, Quebec City).
But in general, I would rather not ignore any threat. And I often get the sense that those who complain about the Muslim threat are more motivated by diverting attention from a threat than bringing attention to a threat.