I'm hoping to write up a super-post detailing different HP+healing systems, and the pros and cons of each system.
But in order to actually do so, I need to get your input on what the possibilities are, and what you see as the pros and cons of each.
I'll be using the terms “long-term” and “encounter” resources, as I feel daily resources can generally be changed into weekly, monthly, or even (if you feel the need) yearly resources.
What type of resource could HP be
A purely long-term resource. Impossible to restore/heal except through long-term resting. (like AD&D without clerics)
A primarily long-term resource. Can be restored, but the ability to restore it is very limited; requiring significant long-term resources. (like AD&D)
A primarily short-term resource. Can and will be restored, but restoration costs some amount of long-term resource, which will eventually run out. (like 4e, or 3e without CLW wands)
A purely short-term resource. Any damage that doesn't kill you is irrelevant once the encounter is over, as you can heal it all up without using any significant long-term resource. (Gamma World, or 3e with CLW wands)
With options 2 and 3, there's another question:
What form does the long-term limit take?
A) The limit is on the amount of healing that the healer can do. For example, a limited number of spellslots which can be used for healing spells. (This is the pre-4e approach).
B) The limit is on the amount that the individual can be healed: either they expend a resource when healed (Healing Surges in 4e; people on here have suggested Heroic Surges instead, which would be usable for more things) or they take some form of more lasting damage (ie Wounds).
C) A+B. Some healing comes from the resources of the healer, while other healing comes from the resources of the healed (ie. 4E, with surge-less healing such as Cure Light Wounds; or a wound system with some spells that heal wounds).
D) A or B. All healing is limited by both the healer and the recipient of the healing.
Split HP: Rather than a single pool of HP; you have two separate pools. (Example: SWSE with Vitality Points and Wound Points) Each pool obeys its own set of rules.
Temporary damage. Half the damage you take in any given encounter is automatically restored at the end.