I think one of the worst ways to die would be...

To have your epidermis ripped off a portion of your body at a time, then cauterized so you wouldn't bleed to death. From there, your feet and legs and arms are wrapped in barb wire and you're dropped into a bathtub of lemon juice. After that, you're forced to walk yourself to a big vat of salt where you're pushed in. After all that, you're let free. But...you have to get up the steps that are covered in broken glass and tacks.

But, hey...that's just how I wouldn't want to die....

Edit: I'm not entirely sure this would kill you. Maybe you'd just wish to GOD you were dead.