Just like the Warlock and the Mage the Priest is a pure cloth wearer. While this greatly reduces his choice of items, but since there are three cloth classes, cloth drops are not really rare. A Priest is able to wield daggers, maces and staffs as weapons, so unlike his fellow cloth wearers he is unable to use swords and not able to wield fist weapons like Druids and Shamans. As a rule of thumb staffs have more pure stats like stamina and intellect while an main-hand / off-hand combination provides more spellpower and secondary stats.

Intellect and stamina can be found on nearly every piece of cloth armor and naturally these stats are useful for a priest. Spirit is a very strong stat for a Holy Priest and a good stat for a Shadow Priest as well. Naturally every Priest Spec needs spellpower to increase the effect of their damage and healing spells. A Shadow Priest will need 11% spell hit chance on his equipment to prevent misses against boss level mobs. Holy and Discipline do not care about hit rating, except maybe in PvP. Haste and crit rating are of interest to every Priest spec. Individual taste dictates the value of these stats.

Of no value to any Priest are stats like strength, agility and armor penetration. Luckily these stats are usually not found on cloth armor, so you aren't tempted to take these stats. It might be annoying that cloth armor is sometimes interesting to non cloth wearers as well, as those are sometimes the best choice for other classes. The sheer amount of cloth drops can make up for this annoyance though.