Should convicted murderers be executed?? (Criminal Law)

The question is still asked, even today, Should convicted murderers be executed? Many arguments have been conducted over this question but none have been fully taken into serious consideration. Depending on many of the crime situations, convicted murders only serve 12-25 to Life in prison.
Articles and continuous blogs have been discovered on this particular question. They also show the pros and cons of the death penalty, also known as capital punishment. Some people call the death penalty "Cruel and unusual", Some even say it should be abolished for good. With a good side comes a bad as well, people who oppose the previous statements say "The death penalty is the best thing that could have happened to this city and most importantly the world. I say who should really decide how to gamble with the lives of these convicted felons.
In the article of New York Times, which was published in 1895 agrees with giving the death penalty to convicted murderers.  Back then convicts had more of a chance to escape a death trial than a homeless man trying to retrieve a slice of bread.
Some people take this topic into religious matters (Example):
Steven Hayes, a 47 year old convicted  murderer is on trial for the death penalty. The charges were the murder of three minors and the mother.  Dr. William Petit Jr, father and husband of the victims was asked to stand in trial to testify for this matter.The jury sentenced Hayes to death on six counts: killing Hawke-Petit (mother) and Michaela and Hayley (daughters)  in the course of a single action; killing a child under the age of 16; also on the count of kidnapping  and the count of sexual assault.The family was tortured for 7 hours straight, while the husband had been badly beaten and unconscious.
Which brings me to the point of should convicted murderers be executed? When interviewing people on the streets I would ask these variety of questions: Should ALL convicted murderers be executed? Would you judge a murderer who committed crimes 10 or more years ago? Would the streets be safer with all murderers put behind bars? These questions may impact some people because they have family who are convicted murderers and were on the verge of being executed.
In my  personal and strongest opinion I believe convicted murderers should be punished for their crimes but I don't believe that all should be executed. When looking into a murder case, you must look for the purpose of the murder and the most important part "State of mind", but look carefully you might be executing an innocent male/female or traumatically executing a mentally retarded person.

U. S. Supreme Court: Roper v. Simmons, No. 03-633 |