I am for the death penalty if there is undeniable evidence, including DNA that the person to be executed did in fact commit the crime in question. I'm very, very much against it. Even in the US, where the execution is supposed to be humane, it often isn't. Lethal injections are supposed to be the most pain free method of execution, but many people say they cause immense pain. In other countries it can be barbaric.
Some countries still practice stoning for serious crimes.
I read about a man who was stoned to death for rape and murder - he was buried up to the waist in sand and stoned, it took him more than 5 hours to die. The biggest problem with Capital Punishment is that someone who is against it can read what I just wrote and see it as terrible. Someone who is for it can read it and agree that the punishment fits the crime. Sometimes, death is gentler way, than the rest of your life. It isn't like you get put to death for petty crimes.