There is lots of news and commentary addressing the question of using torture. The typical arguments against it revolve around the notion that we are better than that, torture is not effective (a person is pain will tell you what you want to hear, regardless of whether it is true), and torture violates domestic and international law. I haven't heard what is, for me, the most important reason for this.
There was a time in our history (think Spanish Inquisition, witch trials or any inquiry by an angry or frightened dictator) when the interrogation methods were essentially punishment. If such interrogation methods were legal, trials were essentially meaningless. If you could be put on the rack and your bones broken in the process of trying to extract a confession or "gather information," then the fact that you might eventually be found innocent is rather poor consolation. Torture as a means to extract a confession is essentially a guilty verdict without a trial.
The modern world with rights for the individual is at odds with torture for this reason. It is both this simple and this complex. Once you begin torture as a means to determine guilt, you've corroded rights.