The 'no deterrent' argument is rubbish - taking that to its logical conclusion you could argue the threat of a custodial is no deterrent either and therefore we shouldn't bother having prisons at all.
State sanctioned 'murder' is also rubbish. This is a weak argument trotted out using an emotive term to force home a wrong point. If it is state sanctioned, and therefore legal, it cannot be 'murder'.
Rehabilitation should only ever be a by-product of the punishment - the first job of a prison is to punish. Plus, of course, some people cannot be rehabilitated and therefore we shouldn't even bother trying (Huntley, Nielson, Whiting etc...).
Despite the above, I am fervently against the death penalty, not because it is not a deterrent (because the deterrent argument doesn't hold water), not because it is state sanctioned 'murder' (which it is not), but simply because there would be innocent people killed.
An appeal proving non-guilt when you are already six feet under, may be nice for the relatives, but bloody useless to the victim of the miscarriage.
Plus, of course, there are the mentalers to consider - if somebody is genuinely suffering from nuttery and they were not responsible for their actions, then I fail to see how they can even be guilty of murder, much less die for it. Although of course we would need to do a Bradley and keep them locked-up in a lunatic asylum.
However, I do believe, in cases such as Huntley, where the crimes are so breathtakingly evil, that life should mean life and the term should be served in a cold, dank, damp cell with just enough basic rations to survive.
But this would be a violation of human rights I hear those of a Guardian disposition nasally whining - well so bloody what?