Seems to me that the terrorists achieved what they wanted in Mumbai with a couple of guns, grenades and training. They'd probably get the same result running multiple simple attacks, or something like what happened on 9/11/01 rather as they would with WMDs.

Still, it may happen of course, but I would think smaller attacks and preparing for them first and foremost would be the best course of action for the average person.

That's just my opinion. I could always be wrong.