A guest post on the Baseline Scenario blog by "StatsGuy" offers a reasoned, thoughtful and well researched take (or rather several takes) on what led to the financial collapse. The essay looks at the concept of "too big to fail" in the financial world as it relates to systemic risk, the decline of the US middle class, and irrational exuberance as causes (either necessary or sufficient) for the Big Bust. Discussing the causes of the debacle is important to deciding what to do about it, of course. And the gist here is that getting all TR on the oligarchs of Wall Street -- worthy as the cause may be -- probably should be a lower priority at present. Along the way, the essay links to numerous informative publications, including this exhaustive timeline of political decisions that led up to our current mess.
Unlike most blogs, the readers' comments at Baseline Scenario are often as good as the articles themselves. I recommend reading the whole shebang.
On a related note, William Black's 2005 book The Best Way to Rob a Bank is to Own One probably should be on my reading list.
Some will rob you with a six gun and some with a fountain pen...