I'm not sure how I feel about capital punishment, as one one hand you have basically state side murder, whilst on the other, you have to support that criminal often for the rest of their life, leading to wasted taxes in my opinion.
The trouble is, you still end up paying at least as much, regardless, so a cost argument really isn't effective.
I agree with the point that until its 100% proven guilt, the death sentence should never be applied. Innocent people should never be executed! However I don't see the point in trying to rehabilitate the most violent members of society. I'd rather let pharmaceutical companies use them for human testing then allow someone like Anders Behring Breivik out of prison.
If we were to do that, what would it make of us? I feel that we should try to rehabilitate even the very worst of us, because ultimately it is the right thing to do. However, I do appreciate that there are those who cannot be rehabilitated, and thus would never be safe for release, and that is fine.
The chances of Breivik actually being released from prison are rather slim. He has shown no remorse for his actions, which would do him no favours in any argument to secure release on grounds of rehabilitation, and so his sentence would likely be extended at each review.