Strength

   Strength primarily affects how much you can carry. 
   Just take the number, multiply it by 10, and you will know
   how much you will be able to hold.
   
   THe secondary effect of strength is how much damage you do.
   Usually after your strength has gone above 20, you will start
   to recieve a damage bonus.

Dexterity

   Dexterity affects your armor coefficient AC. THe higher 
   dexterity is, the lower AC is, the harder it is to hit you.
   IT also affects the chances of you to hit monsters. THe higher
   dexterity is, the more chances you have to hit them.
   After dex is above 20, you start to recieve a time bonus, that is, 
   how fast you can hit, move, recover from fumbles and such.

COnstitution

   COnstitution plays a major role in how much physical damage
   you take. THe higher con is, the less physical damage is done 
   to you, and the more health points and stamina points you can 
   regenerate in each tick.
   After con is above 20, you start to recieve a bonus in stamina
   and health points.

Intellligence

   Very important when dealing with magic. High int results in 
   long-lasting resists, devastating offensive spells and low 
   magical damage (from spells).
   It also affects how much money you get in a store when you sell
   items. The chances of successful 'search' of a hidden item 
   increase as your int increases.
   After intelligence is above 20, you start to recieve a bonus in 
   mana points.

Piety

   Important for mana regeneration. The higher it is, the faster 
   you regenerate mana points. It is very important for faith-type
   classes, as it increases their chances for a successful turn of
   an undead.

Barbarian

Strength--higher bash damage
Constitution--less damage taken


Bard

Piety--bards are fine healers. As they use faith magic, piety is 
       important.
Intelligence--for better spell casting


Cleric

Piety--fast regeneration for constant healing
Intelligence--spell casting


Fighter

Strength--better bash and harder hits
Constitution--less physical damage


Mage

Intelligence--spell-casting ability
Piety--fast regeneration


Monk

Strength--hard hits
Constitution--less damage
Piety--faster chi regeneration, ability to meditate
Dexterity--touch of death, low AC
Intelligence--resistance to spells


Paladin

Piety--healing spells, turn
Strength-hard hits
COnstitution--lower physical damage
Intelligence--spell-casting


Ranger

Dexterity--hide and sneak 
Strength--ability to hit harder
Intelligence--rangers are fine spell-casters


Thief

Dexterity--hide, sneak, pick locks
Constitution--less physical damage