Light Armor
Light armor in "Dragon Age" is usually made from leather. You will most likely encounter rough leather first, which requires 10 strength. After that, you get cured leather (11 strength), leather (12 strength), hardened leather (14 strength), reinforced leather (17 strength), inscribed leather (18 strength), drakeskin (20 strength), dragon wing (22 strength), and high dragon hide (24 strength). The type of armor you choose will influence the amount of fatigue your character has to deal with. Lighter armor causes less fatigue, which is useful for certain classes. A mage, for instance, will do better with light armor as he needs mana (which decreases with fatigue) to cast spells from a distance.
Medium Armor
Medium, heavy and massive armor are all made from the same materials, but require different strengths to wear. Medium armor provides less protection and requires less strength (between 14 and 34) than the heavier equivalents. The materials are: iron, grey iron, steel, veridium, red steel, silverite and dragonbone. Soe unique armor sets give you extra enhancements for battle, such as increasing your stamina, dexterity and your resistance to fire, nature and spirit damage. Examples include the Ancient Elven armor, the Shielded Dwarven armor, Varathorn's armor and Wade's Dragonskin armor.
Heavy Armor
Heavy armor provides more protection in combat but requires more strength and causes more fatigue. As your warrior would be in the midst of the battle most of the time, it is a good idea to equip him with either heavy or massive armor as soon as possible. Heavy armor sets are made from either metal or dragonbone (see medium armor), requires strengths from between 18 to 36 and will increase your character's fatigue by between 14 and 19 percent. Some unique heavy armor sets have enhancements that will decrease your fatigue, others promote stamina or health regeneration in battle.
Massive Armor
Massive armor sets provide the most protection in "Dragon Age" -- but also cause the most fatigue. You are more likely to encounter these sets later in the game as your character grows stronger. Armor is made from either metal or dragon bone and requires strength from 22 up to 42. There are quite a few unique sets that provide extra enhancements, such as the Corruption armor, the Effort armor set, the Juggernaut armor and Wade's Superior Dragonbone Plate armor set.