I take your "what now?" question literally what should "we" do the people reading and writing these? Not "we" the political entities of the West or "we" the heirs of civilization. It strikes me that in these times, the answer is actually quite clear, and it has to do with the great flexibility of that concept of "we."
As a number of people have observed over the years, human beings have a mighty capacity to line up with the rest of their team against some other team, but this mental structure is not committed to any particular content. You might think of it as a syntax without any semantics: We know how to do Us vs. Them, but I have yet to see a persuasive case that any particular form of Us (ethnic, nation, class, religion, even kin) is "built in." So when "we" are attacked we have a cognitive problem: Defining what "we" means. And the problem is of vital importance, because the answer we use doesn't just interpret the world for us, it guides future actions. The story of the attack shapes our response, therefore it matters a great deal what the story is.
And this struggle to define what "we" means is what I see occurring all around me, in New York City, in the United States, and in the world. It is, of course, taking place in billions of individual minds, so the answers vary, from President Bush announcing that our quarrel is not with Islam to the people down the street from me saying they should round up all Arabs in this country. (They are, by the way, neighbors to an Arab family, whose son is away he's in the US Army). But it is not purely a matter of individual psychology. Some concept of "Us" will succeed, and become part of what Lyotard calls a master narrative of this conflict. It will be the widely shared representation of what our side is, as the story of the American Civil War (not settled until 1863) was "we are those who fight slavery" or the story of World War II (not settled until the 1940's) was "we are those who are destroying totalitarianism."
We are all in the early, unsettled stages of defining our side. Within Islam and within the United States, there are those who speak in terms of God and the sins of nonbelievers. In Europe, I see, at least one Premier has proclaimed the superiority of "Western civilization." Our own president here used the unfortunate word "crusade." It is not inconceivable that in this struggle the "we" definition that succeeds will be Islam vs. Non-Islam; or North vs. South; or the West vs. the Rest. Many of these potential definitions point to a world where "our" victory would be scarcely better than "our" defeat. (In a war of Christianity vs. Islam, where is an atheist materialist going to go?)
So, now what? People on the Edge list should now engage in this worldwide struggle over what it means to be on "our" side. We must fight the rhetoric of metaphysically pure communities, of clashing civilizations, of mystical cycles and divine interventions, and work to shape a definition of "our side" which will be worth fighting for.