I think death penalty is a good option regarding to some especific situations, when the subject in charge has made a horrible crime, something unpardon, unexcusable. I don't want to start especifying due to what crimes, I'm just saying that it would be important in order to make justice in face of a mean crime... I don't believe that a prison can recover a bad criminous, thus it would be better kill him, in order to preserve and keep the society safe from this kind of mean.
As our friends mentioned above, our judicial system isn't preparred to a death penalty, since it would take plenty of qualities and cares which I particularly don't see in charge.
For sure, this question is very conturbate and requires more reflection in such a way that the whole society takes place on that.