Death comes in many guises, but one way or another it is usually a lack of oxygen to the brain that delivers the coup de grâce. Whether as a result of a heart attack, drowning or suffocation, for example, people ultimately die because their neurons are deprived of oxygen, leading to cessation of electrical activity in the brain - the modern definition of biological death.
If the flow of freshly oxygenated blood to the brain is stopped, through whatever mechanism, people tend to have about 10 seconds before losing consciousness. They may take many more minutes to die, though, with the exact mode of death affecting the subtleties of the final experience." Here are a couple of highlights:
Drowning: "There is a feeling of tearing and a burning sensation in the chest as water goes down into the airway. Then that sort of slips into a feeling of calmness and tranquility."And if you find this article interesting, I highly recommend you read Stiff by Mary Roach.
Decapitation: "Beheading, if somewhat gruesome, can be one of the quickest and least painful ways to die - so long as the executioner is skilled, his blade sharp, and the condemned sits still."
The song of the day is "Little Black Backpack" by Stroke 9 off their 1999 album Nasty Little Thoughts. I heard this song on KROQ a couple of times and liked it enough to buy the CD which was surprisingly good through and through. It still finds its way into my car now and then. Unfortunately, the band never fared well and were dropped by Universal Music after their follow up album and are now releasing records independently. If you've never heard it, you can listen to it here.