@NeoconMan: crucifixion was a Roman (amongst others) practice, not a Christian one. The Christian tradition is massed swords, arrows, cannon and gunfire for groups, alternatively torture then burning alive for individuals.
@gammaguy: indeed, carbon monoxide is probably the cleanest, safest, most hygienic and most humane method available. It is ironic that the generator(s) used to run the electric chair probably produce enough CO when cooking one person to death to kill everyone on death row. (Also, it was a method used by both the Nazis and the Soviets, so should be acceptable to both the political left and right.)