I'm 100% for the death penalty.
People like to say that the death penalty is not a deterrent, but I know this: 100% of those executed did not go on to commit other crimes.
And, as expressed previously in this thread, is the fear that the wrong person could be executed. There have been numerous examples of people on death row who have had their convictions overturned. Capital Punishment, as it is practiced in those American states where it is on the books, has layers upon layers of appeals that gives the condemned, if they are truly innocent, a chance to be exonerated. Even a person who waives their appeals and wants to be executed will wait anywhere from 10-20 years before they get their wish.