all it takes is one world super power (eg US) to drop a nuclear bomb on their 'safe havens' and there is no more Al-Qaeda network
You forget that these networks are spread all over the world, and particularly through greater Europe. I saw a TV program in April (ABC I think) that covered some of the intelligence info Interpol and the CIA had on these groups. Among other things, it focused on moroccans leaving their home country for different parts of Europe. In looking to meet other Moroccans, these young men were often prayed upon by the recruiting groups who trained them up for such operations.
What was truly amazing and quite terrifying in itself, is that when a cell was uncovered, it was often found that the instigators or group leaders were completely unknown to authorities, and even worse, impossible to trace where they'd come from or their true identities. The conclusion was a bleak forecast that the west hasn't got a hope....
these guys arent intelligent, they are desperate
I think it's naive to think these groups aren't intelligent. They often have university education and better. Something which you also don't hear much about concerns the weapons/ bombs potentially at their disposal. Following the Bali bombing it was evident that chemicals other than nitrates, nitro compounds etc, can, and are being employed in making improvised explosives.
I won't go into what some of these things could be, but I will say that it would be practically impossible to scan for all the possible ingredients that could be used to make such a bomb. IMO the worst is indeed yet to come, and I don't believe for one moment Australia is any more protected or safe than England. In fact, because of the large unoccupied regions, it could prove to be far less safe. Just my opinion of course....