I use a few different systems all in one for my equipment.
First of all there are tiers of items: Tier 1 - Tier 6:
Wood - Bronze - Iron - Steel - Mithril - Adamant
Following tiers, they have a chance of rolling a random affix:
Of Endurance, of Power, of Defenses, of Speed, etc.
Following that each item can roll a different rarity. A higher rarity means higher stats for that item.
White = Common (no bonus)
Green = Uncommon (3-5+ on stat(s))
Purple = Rare (6-10+ on stat(s))
Yellow = Super Rare (11-15+ on stat(s))
Cyan = Legendary (16-20+ on stat(s))
In essence, there are really only 6 basic weapons tiers in my whole game, but because of all the different secondaries they could possess once acquired, it provides hundreds and hundreds of variations. Even a simple Green Bronze Sword of Power could have different stats from an exact same sword that drops. Think Diablo, for those of you who are familiar.