While I'm glad that the conclusions of the newly released NIE have pushed the prospect of an inevitably disastrous Iran invasion substantially farther off the table for now, I think we're still left with very serious questions both about the brazenly dishonest process by which the President, the Vice-President, and their apparatchiks were clearly trying to build support for war with Iran based on a nuclear threat which we know now they knew to be nonexistent, and about the ideology which underpinned this effort.
To build on what Rob said, I think that perhaps the most important determination of the NIE is that Iran's "decisions are guided by a cost-benefit approach rather than a rush to a weapon irrespective of the political, economic and military costs." That is, despite some high-flown Iranian rhetoric (and decades-old Khomeini quotes of dubious provenance) Iran's behavior indicates that it is taking a rational, pragmatic approach to its role as regional hegemon. It is clearly not behaving like the "nation-as-suicide-bomber" that Norman Podhoretz and Michael Ledeen see in their oatmeal every morning.
In the paranoid arguments of the neocons, we are at war with a single, monolithic enemy: Islamofascism [sic]. This enemy may have many faces, but it is, in the end, a single force. As this enemy worships death with the same intensity with which it hates freedom, it cannot be negotiated with, it must only be defeated. It's no overstatement to say that the NIE released yesterday has dealt a death-blow to such arguments. No matter how often such analogies are (and will probably continue to be) deployed, it is not 1939, and Hitler's army is not massed on the border. It's 2007, and these guys don't know what they're talking about.