I have always been averse to the death penalty for quite inexplicable reasons; it merely seemed absurd to me. But then last night, Camus said it for me:
An execution is not simply death. It is just as different from the privation of life as a concentration camp is from prison. It adds to death a rule, a public premeditation known to the future victim, an organization which is itself a source of moral sufferings more terrible than death. Capital punishment is the most premeditated of murders, to which no criminal's deed, however calculated can be compared. For there to be an equivalency, the death penalty would have to punish a criminal who had warned his victim of the date at which he would inflict a horrible death on him and who, from that moment onward, had confined him at his mercy for months. Such a monster is not encountered in private life. (1957)

Not to mention of course, that such a punishment is useless. You cannot bring back the victim's life by killing their perpetrator, and I highly doubt that the death penalty ever stops anybody capable of murder, from murdering. I presume a fair proportion of people who are committing crimes severe enough to warrant the death penalty, are doing so because life holds little value for them. When it has gotten to the stage where you are murdering people compulsively, you've got to be pretty empty. Either that, or slightly mad, and if you are mad, well punishment's just not the same. Death would likely be a welcome gesture, to end the struggle and the pointlessness and the absurdity of living. There must be far more efficient punishments, than merely an end, a relief.