Aargh! I typed the whole thing up, then got disconnected and couldn't get my original message to come back.
Let's try this again. Sorry, I am going to be brief this time.
HP determination:
Edit: I don't use this rule anymore. It was more trouble that it was worth; I didn't spend enough time at low levels to worry about it. But here it is:
[sblock=Old HP Determination rule]
All characters that do not have at least 2HD per race get one base HD in addition to their class HD at first level. Con modifier applies. This HD does not count for anything but HP. You do not maximize this HD at first level as you do your class HD.
Why:
First, I think lethality is too high at low level. Second, it helps compensate for the slightly more unpredicableness of combat incurred by the later rules.
[/sblock]
Hovering at death's door
This variation of the standard rule is used to prevent the "I'm at -2 HP, you guys have 8 rounds to save me" syndrome encouraged by the set limit of -10 HP prior to death in the DMG page 104. Wounds from actual combat tend to be much more unpredictable and serious than such a fixed number.
To represent this, instead of using the -10 HP set limit to determine when a character will expire, when a character drops below 0 HP, the DM secretly rolls a constitution check for the character. The result represents the negative number (instead of -10) the character can go to before perishing.
In all other ways, use the rules under "hovering at death's door" in the DMG to determine the effects of going to a negative HP total.
Injuries
The D&D damage system is often abstract, but occasionally even the hardiest of heroes have to grapple with the effects of grievous wounds.
This is a variant of the clobbered rule. If a character takes more than half of their remaining HP in a single blow (to include damaging spells) there is a chance that there is a lasting effect to the injury.
If a character takes over one half of their remaining HP in a single blow (including spells or other effects), the character must make a fortitude saving throw with a DC equal to:
10 + ½ damage dealt by blow
If the save is failed, the character suffers an injury. Take the unmodified result of the D20 roll and compare it to this table:
D20 roll
1-3 Clobbered
20 Limb maimed
For any other result, divide the result by 4, call the result N and remainder R and consult the following table:
R Result
0 Ability damage N points
1 Bleeding N points per round
2 Impair -2 x N
3 Stunned N rounds
(I use this odd table because it is easy to memorize. I simply remember ABIS.)
Effects of the table are as follows:
Clobbered: the character can only take a partial action on their next turn.
Ability Damage: the character suffered a weakening injury and suffers the listed amount of damage to one ability score. Roll 1d12 to determine the affected ability score:
D12 roll Ability Affected
1-3 Strength
4-6 Dexterity
7-9 Constitution
10 Intelligence
11 Wisdom
12 Charisma
Bleeding: the character immediately takes the listed number of points of Con damage and begins to suffer HP damage from bleeding, at the rate listed per round. The bleeding rate may be reduced by 1 point by a healing roll at a DC equal to 10+the bleeding rate, or a Con check equal to 15+ the bleeding rate.
Any magical healing applied to the bleeding wound stops 1 pt/round worth of bleeding instead of 1 HP of damage if the bleeding is not stopped. Any healing beyond what is required to stop the bleeding is applied normally to HP.
Impair: consult the hit location table for the target creature. A limb or other body part is stricken, impairing the functions listed on table 67 of the DMG. The penalty is -2 per the listed number.
Stunned: the character is stunned for the listed number of rounds.
Limb maimed: As with limb stricken, except the character cannot use the affected part until treated by a regeneration spell. If the head is hit, the character is slain.
[imager]http://enworld.rpgshop.com/images/uploaded/locationd12.jpg[/imager]
Hit Location
I used to use a fancy table for this, but it too was too complicated to memorize. Now I simply use a dice size equal to the creature's number of limbs +2. One result is the head, another is for "other" results (DM choice.)
Edit: I now use this dice (pictured at right) for hit locations:
http://enworld.rpgshop.com/product_info.php?products_id=36953&