The death sentence is an ineffective deterrent. Most people think, "it'll never happen to me". People have an irrational belief in their own immortality, possibly because to believe otherwise would be unbearable. So, given the many other problems attached to the death sentence, it's just not a good idea and should be scrapped wherever it is still on the books.
With no death penalty, what is the harshest deterrent we have? Life imprisonment? Pretty bad but lacking a certain sharpness. Corporal punishment? Still used in some parts of the world but for some criminals it's just a rite of passage. So what's a real deterrent?
My guess is that your average criminal has a fairly healthy fear of buggery but without the same irrational belief that it could never happen to them. So what we need is to introduce public buggery as a punishment for serious crimes. Imagine the scene in the courtroom. The judge hears the guilty verdict from the jury and then, turning to the defendant, he places a pink cap over his wig and says "For the heinous crimes you have committed, I sentence you to be taken from here to a public place where you will receive a vigourous and unlubricated seeing-to by a man of not less than 8 inches." A scene which would strike fear into the hearts of the most hardened criminals.
There are several advantages to this. Unlike capital punishment, public buggery is not permanent and so a miscarriage of justice while unfortunate, is not such a disaster. Also, you could sell tickets and TV/video rights.
There are some problems though. There are those who would be only too happy to receive such a sentence and it would be terrible to have people committing serious crimes in the hope of receiving this punishment. So it would probably be necessary to make it available on the National Health. Every cloud has a silver lining - this would create jobs.
It's one of those 1 in a million ideas with no downsides!