I think they will try to bomb the White House again. They failed on the first attempt on the WTC but tried again and succeded big time. I think they will try again to get the White House. Whatever they do it will be big and terrible because anything less than the WTC would look like they are getting weaker instead of stronger.
And if they were to succeed, the end of life in the the middle east will cease to exist as they currently know it. The desert will glisten as if the sands had turned to glass.
I pray they aren't that stupid, but my logic tells me otherwise.