Capital Punishment is defintely bad...Now keep in mind that I have never had anyone close to me murdered, so I may feel differently about this were that the case.
However, statistically speaking, in the U.S. that is, states that still engage in captial punishment actually have higher murder rates than the states that don't.
Another thing, most murders are committed by people the victim knows in the heat of passion. It doesn't matter what deterent (ok, my spelling sucks) is involved in cases like those.
Solution, make murderers spend the rest of their lifes building other prisons, no parole, no cable, no air conditioning. A library is acceptable. Make them sew their own clothes and grow their own food. This will never come to pass, but I think it is a much more humane and prudent way to dispose of murderers.
When you hit and humiliate a child, the only the child learns is to hit and humiliate others. How can we condemn murder, but condone th same act as punishment. It's not right. Think on it.