Body Armor
Body armor generally refers to the protective items integrated into motorcycle clothing. In a broader sense, it could be defined to include helmets and boots, but for purposes of most discussion we are referring to that which is related to clothing and gloves.
Fabric/leather
As opposed to most fabrics, leather provides the best protection from abrasion in the event of an unintended slide down the pavement. Nevertheless, many of the synthetics have reached a level of durability that approaches leather, particularly when reinforced with rigid or semi-rigid armor at key impact points. Blue jeans are not in the "protection" category, and it is often noted that blue jeans provide barely more abrasion resistance than unprotected bare skin.
Removeable armor
Most external motorcycle clothing is equipped with permanent or removeable protection. Areas of focus may include shins, knees, elbows, shoulders, back, and sometimes chest. Also, for trail riding most riders will add external chest and back protection.
Under-clothing armor
Instead of armor built into clothing, sometimes armor separate from the clothing may be most convenient. For example, knee and shin guards can be worn under blue jeans. Some vendors provide sets of full body armored under-clothing.
Armored gloves
For best protection, gloves should have some degree of solid knuckle reinforcement. Sometimes the reinforcement can serve a dual purpose and also provide ventilation. With or without reinforcement, the gloves should have some sort of retention mechanism (typically velcro) so that they do not slip off a rider's hands at first impact.