Torture/Physical Punishment Versus Life Imprisonment

Below, Orin asks a great question: why targeted assassinations are so much less controversial than is detention + waterboarding.  I’ve wondered about that myself.  I’ve also wondered why the infliction of physical pain on someone, assuming he’s not just a suspect but been convicted of a crime, is considered beyond the bounds of human decency by all respectable sources, but locking that same individual in a cell for the rest of his life is a-ok.

Put it this way, would you rather be given 50 very painful lashes for drug possession, as some “primitive” countries do, or be locked away at a maximum security prison for even five years, much less for life?  I know which one I’d choose…