I think Richard Miniter's book - Losing Bin Laden - sums it up well... He talks about training camps and Koranic verses chanted during their training excercises.
It goes like this...
"I will be patient until patience is worn out from patience."
They could attack tomorrow, or it might not come together right. They will sit and wait until the time is right. One thing Americans do not have is patience, and in the end... that may be our biggest fault in this battle.