Updated for patch 3.2 Nothing has really changed. Most gear will get you hit capped very quickly, so you want strength, strength, and more strength.
Retribution Paladins rely on strength as their main stat, and it has been that way for a very ong time. This list is what is considered optimal, but keep in mind that every person has different gear, so you may need to make some small adjustments based on what gear you are wearing.
So as a quick refresher, here are the stats you should be gemming for as a retribution paladin:
1. Hit
2. Strength
3. Expertise
4. Critical Strike
5. Agility
6. Haste
7. Armor Penetration
8. Attack Power
1. Hit - Hit affects your hit %, or ability to hit mobs and bosses. At level 80, Paladins need a total of 8% hit to be capped at 100%, meaning they never miss. Normal melee swings, Crusader's Strike, Judgements, and Divine Storm are all affected by this. Reaching the hit cap should be your number one priority.
2. Strength - Strength is what gives us attack power and increases our damage. After hit is capped, this is what we start stacking. Remember, 1 strength = 2 AP...with the blessing of might buff in the talent tree, it ups to 1 str = 2.3 AP.
3. Expertise - Capping expertise removes a mob's/boss's ability to dodge our attacks. To cap this, you need 26 expertise, or 6.5%. It is recommended to maximize DPS, you have both hit and expertise capped.
4. Critical Strike - From this point on, stats at crit and below are not worth aiming for. They simply do not pack the punch that strength does. Strength should be the stat that ret paladins are stacking hands down when hit and exp are capped. However, crit wins over agility because crit also affects spell crit, whereas agility does not.
5. Agility - Inferior to critical strike, as it takes a whopping 52 agility to get 1% melee critical strike. However, crit does not stack with buffs, like Blessing of Kings, whereas agility does.
6. Haste - While haste seems like a great stat, it currently does not give us a gigantic boost like we'd hope it would. Haste lowers weapon speed, but does not decrease cooldowns on our spells and abilities.
7. Armor Penetration - This ability benefits warriors far more than it does paladins. It affects only our melee white hits, Crusader Strike, and Divine Storm. It does not affect seal or spell damage.
8. Attack Power - Since we hardly see AP on plate items, this isn't really a stat we have to worry about. Plus, 1 strength = 2.3 AP with talents is far superior than gearing up just straight AP. Go for strength instead. The only time a retribution paladin would have to worry about this is if he or she decides to dip into some leather or mail gear.
Remember, this is the ideal rank of stat importance. it varies greatly based on your current gear and talents.
For instance, at this very moment, my rank would be: 1) strength 2) critical strike 3) haste 4) armor pen 5) hit 6) exp because I am hit and exp capped. So, hypothetically, let's say I have 2 chest pieces with equal strength...the first has crit and expertise, while the second has slightly lower crit and armor pen. Since I am expertise capped, I'd choose the second piece, since the first's exp stat is wasted on me. Even though the crit is lower on the second piece, I still would gain more benefit from the additional armor pen.