I voted gunshot. The least desirable part of this is the gruesome mess someone else has to see and then clean up. The pain of someone seeing your brains splattered all over the place would be so horrible, especially for a someone who loves (loved) you. Liveleak videos that show this make my stomach churn, even though the final result of non-existence is what I want more than anything. You can take precautions to minimize the effect of this exposure to others, like doing it someplace police will find you, instead or family/friends finding you, but there is no guarantee, and it isn't exactly kind to the police officer, even though seeing things like that goes with the territory, which they knew when they took the job. I still don't like that part of it. The huge benefit is that it is instant and painless (as long as you hit the brainstem), and once you decide to do it, you don't have time to sit and think about what is about to happen (survival instinct can induce some pretty major and scary panic). With a properly aimed gun, as soon as you have decided to the point that you will die, you are already dead. Even with nembutal, which would be the chosen option for many people, there is a minute where you know you are going to die, and you know there is nothing you can do about it. That could be a peaceful relief for some, but I imagine, even for those who know there is absolutely no way they want to continue living, that a minute of waiting, knowing there is no going back could be just serious panic-time. getting over the survival instinct ain't no easy task.
Edit: I skipped to answer before reading this isn't the 'ideal' method, but the most likely. I don't have a gun, and that will not be my realistic method. my actual method will be inhalation, I'm not sure whether CO, nitrogen, or helium.
