What are your favourite health systems in games? Regular or regenerating health? Maybe hybrids of the two, such as regenerating shields but normal health, or partially regenerating health? Do you like separate HP for limbs? What games have good health systems? What games have shit ones? etc etc etc
Personally, I prefer normal health + medkits to regenerating health, but one of the best health systems I've seen in a game is the one in Far Cry 2. Your health is split into a couple of cells. If a cell doesn't empty, it will regenerate in time. If not, you have to use a healing item to get your health back up.
Limbs having separate health bars is pretty cool too. See Deus Ex and the new Fallout games. You die when you run out of all of your HP, but if any particular limb goes down to 0 HP, it will affect your combat-effectiveness (crippled legs cause you to move more slowly etc).
Deus Ex: Human Revolution as well as the recent Battlefield games have been the best examples of regenerating health I've seen. The regen is slow enough to not be exploitable and for health boosters to still be important.