No, I was actually being quite serious. Ok, a couple of those were stupid suggestions, but nonetheless... if it ever comes time, I'm not leaving anything to second chance.
Duct taping some C4 to my head, and detonating it in a secluded river I'm assuming has a high proababilty of success rate.
Same goes for maybe skydiving from 10,000 feet without a parachute. I would imagine that has a low rate of failure.
I'd definitely never use any of the conventional methods -- hangings, pills, electrocution, etc. We've all heard horror stories about those going bad. Hell, I've heard stories where people shot themselves in the face, and instead of dieing, ended up in excruiciating pain & surgery for months, then had to live the rest of their lives without eyes or a nose.
Sorry, but if I'm going to do suicide, I'm going to ensure it gets done right. As for doctor assisted suicide, I don't know, I'd have to reseach it more, especially the exact chemicals they use. Considering the number of botched lethal injections in the US over the last several years, can't say I'm too confident in it.