A word about light and darkness as regards "Special Advantages" and Special Disadvantages. Darkness, as the game interprets the term, means out of the sun. So, if youre indoors, youre in darkness. Obviously, if youre outside at night youre in darkness, too. Light means outside during the day. For game purposes, you would do well to ignore any light-powered advantages since you will make advancement more difficult and have few chances to benefit from it.
Inability to Regenerate Spell Points: Everyone regenerates their magica reserves when they sleep. If you take this disadvantage you will not be able to. This is a good disadvantage to take if you have chosen Spell Absorption as an advantage or if you have no intention of being a spell-caster.
Damage: A very restrictive disadvantage. If you are outside during the day or enter a holy place (depending on which version you take), you take damage. If you take the Takes Damage from Sunlight disadvantage and use the Cautious travel mode, you will always arrive at your destination when the sun is down. This can be good since youll never have to worry about taking damage while looking for an inn. This can be bad since the people you need to talk to for directions (except innkeepers and merchants) are only out during the daylight hours. Exercise caution in desert areas. Fighters Guilds in these areas tend to count as Holy Places.
Phobia: Youre scared to death of whatever you choose and have decreased chances to hit, less damage inflicted and a harder time defending yourself against the type you choose. Take this one with extreme caution.
Light-Powered Magery: You have problems casting indoors or after dark. If you take decreased ability, then youll have fewer spell points under those conditions and your spells will have a greater chance of failure. Otherwise youll be unable to cast at all in those conditions. A good choice if youre planning on being a non-spell caster.
Darkness-Powered Magery: You have problems casting in sunlight. If you choose to be unable to cast in sunlight, you will lose all your magica reserves when you step outside during the day. Decreased ability means you will lose part of your reserves and have a greater chance of spell failure. This is a good choice for a non-spell-casting character.
Taking Increased Magery 3.0x and Reduced Ability in both Darkness and Light will result in your having more spell points than the default (youll get about 2x Intelligence, not 1.5x as youd expect), but will seriously drop the difficulty dagger.
Forbidden Weaponry: You cant use weapons of the type you select. You can own them, carry them in your inventory and sell them, but you cant equip them.
Low Tolerance: You will be particularly susceptible to the agent you choose. This will usually mean youll take maximum damage.
Critical Weakness: Coming into contact with the agent you choose could kill you as you will take serious damage from it. Racial benefits take precedence over class penalties, so High Elves should choose a critical weakness to paralysis if they are going to use class disadvantages. There is a loophole in the program which can be exploited to your benefit. All harmful effects are checked against your magic resistance before they are checked against other things. For example, if you are bitten by a Spider (which has a chance of paralyzing you), the check is made against your magic resistance before it is checked against your resistance to paralysis or poison. If you have taken "Immunity to Magic" as a class advantage, you can give yourself a critical weakness to Poison, Paralysis and Disease with a fair amount of safety. The catch is that if you fail your magic immunity check, you will usually take full damage because of the critical weakness. The combination will bury your difficulty dagger in the red, though.
Forbidden Armor: Choose your poison: Leather, Chain or Plate. You cant wear it. You can own it and sell it, but you cant equip it. Taking the disadvantage of being unable to wear Leather or Chain can be a severe handicap very early in the game, but will be unnoticeable once you hit 2nd or 3rd level. By the same token, being unable to use Plate is not much of a disadvantage early in the game, but a major obstacle at later stages.
Forbidden Shield: You cant equip shields of the particular type. Bucklers provide +1 to your armor class on the shield side, Round Shields give +2, Kite Shields +3 and Tower Shields +4. As a recommendation, if you have to take this, skip the Buckler since it only provides +1 and skip the Tower for weight considerations. A bit more on this under forbidden materials.
Forbidden Materials: You cannot equip any weapon, shield or armor made from the selected material. You can almost always afford to lose Orcish since theres so little of it running around in the game youll never even notice its loss. Depriving yourself of Iron, Silver or Steel might hamper you early on, but will be almost unnoticeable once youre past 5th level.
Ranked from lowest to highest for weapons: Iron, Steel, Silver, Elvish, Dwarven, Mithril, Adamantium, Ebony, Orcish, Daedric. The higher on the list, the more damage the material inflicts and the more it weighs (Orcish being the exception -- it's the heaviest material in the game).
For armor purposes Iron is +3, Steel +4, Elvish +5, Dwarven +6, Mithril/Adamantium +7, Ebony +8, Orcish +9, Daedric +10. You will almost never find any armor (besides helmets and shields) made of silver, but if you do, it's +4.
For Enchantment purposes (making magic items): Iron, Steel, Elvish/Mithril, Dwarven, Silver/Adamantium, Ebony, Orcish, Daedric. Silver and Adamantium weapons have the same capacity for holding an enchantment. Elvish and Mithril have the same capacity. Silver armor (pauldrons, gauntlets, etc.) apparently has a higher enchantment potential than Daedric, but it is equivalent to steel for protection.
As a general rule youll gain more benefit from losing the better materials than you will for restricting yourself from Iron. Iron is a safe choice, but you wont gain much benefit from it.
The difference is sometimes hard to see (especially with Silver/Elvish and Adamantium/Ebony), but shields are also made from these materials. So you can allow yourself to have a Round Shield, but if you restrict yourself from Iron you cant use an Iron Round Shield.
You can distinguish the materials through the color of the item. Iron tends to be dull dark gray, Steel tends to be shiny gray, Silver and Elvish are both silvery and difficult to distinguish, especially with shields. Dwarven is gold, Mithril is dark blue or blue-black, Adamantium and Ebony are both black, but Ebony tends to have obvious gray highlights. Orcish is greenish-black, and Daedric is red. If you have access to an item maker you can tell the difference between some of these materials by the number of enchantment points the item has. An Ebony Kite Shield has more enchantment points than an Adamantium Kite Shield, but there is no difference in the protection they provide. A Kite Shield is +3 regardless of whether its Iron or Daedric.
Be careful in selecting any forbidden materials, weapons or armor. Some creatures require special materials to be able to hit them. If you lock yourself out more than one or two of the high-end materials, you may have to resort to hand-to-hand combat in order to hit your target. Also, you may very well prevent yourself from using the armor and weapons you start with.
A couple of final words on Advantages and Disadvantages. You cannot cancel them out. For example, you cannot saddle yourself with a critical weakness to poison and take immunity to poison. Also, you should not duplicate any racial advantages. For example, dont take immunity to paralysis if youre a High Elf. It wont do anything except make it more difficult to develop your skills. And remember, youre limited to 7 of each, so choose wisely.