Do murderers deserve the death penalty?

Recently, people have again begun to discuss the issue of whether murderers deserve the death penalty. However, in my opinion, the death penalty is ineffective, risky and barbaric.
In most countries the death penalty was abolished long ago. In my view, there are very good reasons for this. Firstly, capital punishment is not a deterrent. In American states where the death penalty has recently been reintroduced, the murder rate has not fallen. Secondly, the death penalty is final. Mistakes cannot be corrected after a man has been executed. Finally, I believe that murder is wrong and this includes murder, or executions, by the state. As far as I'm concerned, the state has no more right to take a life than an individual has.
In conclusion, I think that the death penalty should definitely not be used in a humane, civilized society.