re: It does indeed sound like you're not among those claiming 9/11 was a setup

I claim nothing except what I wrote.

re: And I'm not averse to every conspiracy theory

What is amusing to me is that the government's version of events is the biggest conspiracy theory of them all, and the rabid believers in it become apoplectic when this is pointed out.

re: what, to you, is the most plausible explanation for the destruction of the towers and the Pentagon?

I have no explanation, nor do I propose one without hard evidence and expert testimony. I'd also like to see such experts properly cross examined.

I merely say that given the government's utter lack of credibility, a proper investigation should be conducted with full subpoena power by an independent panel of experts, not a bunch of political types. There is certainly enough out there that has been written by actual experts that casts serious doubt on the official explanation for the collapses of the WTC -- particularly WTC 7, which the 9/11 Commission didn't even address. And damned if I can find even one clear picture of a plane hitting the Pentagon, which is surrounded by something like 80 cameras. Nor can I figure out for the life of me how a plane even got into the highly controlled airspace around the Pentagon with, apparently, no problema, and proceeded to smash into it unmolested.

P.S. You may be interested in this:

As noted in an article in The New York Times from December 25, 2001, entitled "Experts Urging Broader Inquiry In Towers' Fall":

“…some structural engineers have said that one serious mistake has already been made in the chaotic aftermath of the collapses: the decision to rapidly recycle the steel columns, beams and trusses that held up the buildings. That may have cost investigators some of their most direct physical evidence with which to try to piece together an answer.”

http://tinyurl.com/nvz9dc