The only other books to get any mention were two more tightly focused books related to particular aspects of the catastrophe: 9/11: American Ground: Unbuilding the World Trade Center by William Langeweische, which is about the aftermath of the destruction of the towers themselves, and Perfect Soldiers: The Hijackers: Who They Were, Why They Did It, by Terry McDermott, which looks more specifically at the 19 hijackers.
Still though, the real take away is that virtually everyone who wrote in recommended either The Looming Tower or the 9/11 Commission Report. And that's pretty amazing when you consider that the topic is one that's dominated public life for almost a decade.
One thing I take from this is that Looming Tower must be one pretty damn good book, which doesn't surprise me, given the author. And that the 9/11 Report, which I've read as a reference, but I don't think I ever read cover-to-cover, completely broke the mold of the standard poor-prose, hedged and short-on-imagination or courage government report.
Beyond all this, though, it does strike me that there's something of a lacunae here that maybe requires some explanation. 9/11, for better or worse, is the overwhelming, dominating fact of the early 21st century in the United States. It's just totally suffused our politics and our culture and it's been the proximate cause of the other main contenders for importance, like the Iraq War. And while whole book publishing houses have been kept afloat by books about torture, the Iraq War, scary Arabs and Muslims, threats to civil liberties, terrorism and counter-terrorism, at least in relative terms there seems to be a certain eye at the center of the storm as it were. I stress 'relative', but there seems to be a relative paucity of books about the key event itself and what led to it, even as there are vast rivers of writing on various topics related to it and spawned by it.
Admittedly, this is based on pretty limited research on my part -- just hearing your recommendations and my own sense of there not being a lot of obviously good books on the topic, which led to me asking the question in the first place. And to a degree the Report and the Wright book are probably just so good that they've driven others from the field. (I know a bit about book publishing. And while there's probably good civic purpose to there being a dozen or more big fat books on the 9/11 conspiracy, it's much less easy for a publisher or author to get up the enthusiasm, time and resources to write what will just be yet another book about the same basic subject.) So in addition to your giving me a couple really good recommendations, it's got me thinking of this other question: why this epochal event seems to have garnered so relatively little direct treatment.