Let me suggest a few reasons why I think that last question is the wrong one.
Second, torture has boosted recruitment for anti-U.S. organizations tremendously, horribly damaged the United States' image, stripped U.S. diplomats of the power to address human rights abuses abroad, as well as stripping U.S. citizens of a clear moral right to protest being tortured, and set an example that has spread far and wide. Torture has brutalized participants and witnesses, and we are all witnesses, and it has destroyed lives both through torture to the point of death and through torture to the point of unbearable life.
Third, if you're going to violate particular laws and treaties, you can either repeal them and leave all the other ones intact, or you can simply proceed criminally, thereby assaulting the whole structure of law, leaving everyone in doubt whether ANY laws will be enforced against important people. Our government has taken the latter approach and redefined crimes as "policy differences," which is why torture is ongoing and no criminal penalty will deter its future expansion or the commission of other crimes of whatever sort by high officials.
Fourth, if torture had produced life-saving information, we would have long since heard that fact shouted from every television studio. In fact, we did hear such claims made. They just all turned out to be fictional. In the latest claim of this sort, torture supposedly produced information on the planned bombing of a building in Los Angeles, and this information was transported back in time to the moment at which investigators had already discovered that proposal and laughed heartily at the then-debunked claim that a serious plot had ever developed. The fact that Dick Cheney is pushing this nonsense on us is not actually a compelling reason to believe it unquestioningly.
So, do ends justify means? Is torture just plain wrong even in those cases when it would save more lives than it cost? These are intensely ignorant questions. Ends must always be made to justify any means, but the ends must be understood in their entirety. If one result of an action is damage to the rule of law or exacerbation of international hatred or promotion of senseless fear, that must be part of the calculation. Of course torture would not be wrong in a situation in which, all things considered, it did more good than harm; but that situation cannot be found. Whether you claim to simply adhere to a blanket rule, or you consider all the consequences of your actions, you arrive at the same conclusion: torture must be abolished.
But so must the debate over whether torture must be abolished. Torture is illegal. Our laws must be enforced. Torture's recent prominent use by the United States came about in an attempt to promote a far worse crime than torture, the crime of aggressive war. We should not be asking ourselves whether torture was an acceptable means toward that end. We should be asking ourselves how we can best rid the world of wars of aggression.