I haven't made a study of the subject, but it seems like I still remember every gruesome detail I ever picked up. It's like one of those things you ought to be able to forget, but can't put out of your mind once you've heard.
Hanging is supposed to be instantaneous and humane if it's done right. I've heard horror stories where they messed up the drop and the prisoner either strangled slowly or was decapitated. I don't suppose the Brits do it any more either, but in one novel I read, it claimed that in modern England they used a metal collar for the hanging instead of a noose of rope.
Edison invented the electric chair, mainly as free publicity for Consolidated Edison. I think the story on Wikipedia claimed that his first victim eventually caught fire after sizzling for 15 minutes. Hate to imagine what that smelled like (and i wish i could stop)... There are lots of similar stories, and that hideous scene in the Green Mile. Not my first pick, that's for sure.
I've heard the same stories about Madame Guillotine as JTK, that in the last few seconds before your brain bleeds out, you'd be conscious of your head coming free and tumbling away. The shock might numb the pain of the cut, I suppose. Kinda hard to find survivors and interview them.
Lethal injection is certainly less disturbing for the witnesses, though I'm not so sure how it is for the victim. I think they administer a tranquilizer first, then a paralytic, then finally, a toxin. The paralytic will prevent the condemned man from exhibiting any discomfort...I expect the paralytic would also suffocate him slowly if the toxin fails to do the job, and that sounds nasty.
Don't know much about the gas chamber. Is it still in use anywhere? Cyanide is supposed to be pretty quick, though I expect there'd be a few seconds of discomfort. In some movie I watched, the guards instructed the guy to hold his breath when he heard the cyanide pellets drop into the acid, wait for the fumes to rise, then take one big breath. I suppose the alternative would be a lot of gasping and choking while you try to fight it.
In China, it's a single bullet in the back of the neck, instead of a firing squad. I suppose that preserves the organs and the face. I'm sure I read somewhere that execution day used to be a big spectacle, in an arena or stadium, open to the public. As well, legend has it that the condemned man even has to pay for the bullet.
More humane than the old Chinese Tong gangs when they really wanted to punish someone. The death of 1000 cuts sounds horrifying. It's designed to be as painful as possible, and to keep the victim alive for days while it is carried out. The victim is slowly carved into little pieces while he is alive and conscious.
The Gary Gilmore execution was also a big deal when it happened. He opted for the firing squad too (Utah). Norman Mailer was a witness, and described it in The Executioner's Song. He said that they pinned a target over his heart. I believe the squad were actually in another room rigged with firing holes, like a hunter's blind. After the shot, he bled a bit and raised his hand for a few seconds, then died.
The firing squad strikes me as the safest choice if I had to choose. The worst part would be trying to keep up your courage as you walk out to face your executioners.
