Scut Farkas
Mongoose
I'm not sure about d20 as it exists now, but going back to AD&D, I always understood the hit points to represent more than just health. It was supposed to represent all the dodging, feinting, parrying, etc, that takes place in combat. A level 10 Fighter was not necessarily healthier or stronger than a level 1 fighter, but his experience and skill had increased to the point that his hit points reflected that skill. It's not a system based on realism, necessarily, but it also isn't meant to imply that you are physically taking hit after hit after hit. RuneQuest, in any incarnation, is great for reflecting the grittiness of combat with just enough realism. Too much realism in a game tends to lead down the dark and twisted path of far too many rules to be fun for the players.