It seems like this thread talks about which punishment is more severe.
So I propose another way.
A life-time imprisonment without food and water, just like Terri Schiavo underwent.
If a non-criminal experienced such thing, why don't we implement the same thing to the criminals?
/sevillaugh
Edit:
And we can put the bad guilty guys, who are in the starving-to-death row, in same jails with corpses who were punished the same.
That way we will have the cheapest (and efficient) punishment in the history.
No food, no water, no maintenance and maybe no electricity
We only need spaces to put the bad guys with the corpses.
And it should be relatively short. Probably it'll just take 13 days, like Terri.