Recommendation: **********
Effort required: not very much set up time, but cutting enough holes to ensure death will take some time. you should probably practice a bit first.
Messiness: pretty darn messy. picture an ice-cream pail of blood turned over where you are sitting.
Pain factor: pretty high. slow cuts are surprisingly painful. a sharp blade will reduce this somewhat. soon your heart will be pounding like crazy and you will get really cold before passing out.
Drama: extremely dramatic, even if you survive. wrist scars look cool on anybody.
Certainty of death: not real great. if you cut perpendicular to your wrist veins, you will probably survive. if you cut along the length of your wrist veins they will probably not be able to close up again. even faster and more certain are the inner elbow and the femoral artery.
Wimp option: it should be several minutes until you pass out. you could recover fully during any of this time by firmly bandaging or tourniqueting your cuts.
Other points: Anti-coagulants would go a long way if you know what to take. (Apparently aspirin is a good one.) Try to avoid mangling your finger tendons and carpal tunnels too badly. Hara kiri (slitting your intestines open with a short sword so that you make a Z-shaped cut, also called "seppuku") is considered one of the most painful ways to kill yourself. Cutting open your carotid arteries greatly speeds your death, but I would guess will probably ensure a stroke if you survive. Flowing warm water prevents blood vessels from resealing.
