I don't think its either-or. We know that there has been a long list of coincidences involving Iraq and Osama's agents. We also know that with Afghanistan closed to them the remaining Al Qaedists have taken refuge in Pakistan and Iran. And we know that the primary sources of funding are Saudi, including Saudi Royals, including some in government.
So its important to put the pieces of the puzzle together but not for the point of figuring out if it was Iran, or Iraq, or Saudi Arabia, when there were elements of all three involved at various times.
We have our work cut out for us.