No vote... AQ wasn't one of the choices... (I took Al CIAda as a jab at ourselves)
I think we are finally getting rid of the idea that terrorism is primarily state sponsored when the reality is that it is now ideologically sponsored. The end goal of Bin Laden et al. is the establishment of a pan-Islamic, theocratic region, preferably (to him) the world, but he'd probably start with the middle east in general, and Saudi Arabia specifically. Anyone who would stand in the way would need to be eliminated as a threat. Since in his mind the US and other Western nations are currently supportive of the Saudi royals, and that the Saudi royals are an impediment to his plan, the goal is to weaken our resolve so that we would not attempt to stop him (or his successors) from taking over their 'Holy Lands' (Mecca and Medina) and thereby establishing a radical fundamentalist baseline to the religion.
As for who the government is to say is to blame, I don't see a nation-state on this one. I do think a few countries on the list may do everything they can to distance themselves from any event, however.