Yesterday's discussion about Dirty Fighting sparked an interesting debate between myself and Jack's Tool Box about what a Hit Point actually represented, how they are implemented, and how GM's should be using them. While, obviously, the debate about what a Hit Point is would vary depending on the system, everyone seems to have some pre-conceived notion from their game of choice - or just the first game they played - about what a HP actually is.
So, my question to you today is this: in your own words, what does a Hit Point, or Hit Points as a whole, represent? Is it the ability to turn a potentially lethal blow into a non-lethal blow? is it how hearty and resistant you are to damage? Is it an actual point based way of tracking your character's vitality and life force? What does it mean to you and how should it be used to best facilitate the kind of games you like?
As usual: sound off in the comments.