Paladins are not just Paladins. We have many names, Critadins, Waradins, Retnoobs, Clerics, Healadins, Tankadins, the fact of the matter is that we are the most durable class and can adjust to play in any situation, and only you can decide what type of Pally you want to be.
For those of you looking to play a Healadin, Holy is the talent spec to go with. In raids, everyone who can heal, naturally heals. A Paladin fits into this natural order by staying back and healing, and thanks to their ability to wear plate, can be one of the most dangerous healers in the raid group, if they're played well enough. Perhaps reading this guide will simplify for the work you need to extort while playing your Healadin.
Plate Priest, Healadin (30/21/0)
This talent spec focuses on the talent trees, Holy and Protection. The Holy part of things gurantees that you will be far more substantial at healing during raids, and the additional buffs of armor, defense and the new blessings from the protection tree combine to create a build very good for healers who can live out during the raid, and absorb damage. for Paladins very rarely end up using the same build, although many times they are similar. After speaking with many Paladins, it has been easy for me to determine this as one of the premier builds for a Paladin, as the bonuses to Intellect, the addition of two of the most important blessings (Sanctuary and Kings), as well as the Improved Blessing of Wisdom Buff, makes this a great build for a Healadin looking to be very active during raids.
Being a hybrid class a Paladin has the option to both dps and heal, and it is important to always remember that there is a time for both. Unfortunately there are very few stats that help a paladin in both healing and dps. Getting gear with +Crti% will gimp your healing and getting gear with +Healing will gimp your dps. +Healing/Dmg gear fortunately helps us with both. This build focuses on critting your Holy Shock, Seal of Command procs, and Judgement of Command for dps while still being able to adequately support a team. The 9 points in protection can be moved to either tree as you see fit, I find Guardian's Favor to be the most useful 7 points I can spend, but personal playstyle should be able to take over once you hit your 50-59 bracket and are about to spend those points. For levelling go Seal of Command first followed by working your way to Holy Shock. Gear for this build is easy: Stamina>Intellect = Strength > Dmg/Healing. Luckily for you you can heal in a raid setting as well you sly dog :) .
Reckonbomber, Tankadin/PvP (5/34/12)
The key of this spec is the Reckoning talent, which allows you to build up a 'reckonbomb'. This is done by turning off your autoattack so the extra attacks you gain through Reckoning are saved. You can stack up to four extra attacks in this way, and unleash them all on a single target for some serious damage. Tankadins have Improved Righteous Fury and Holy Shield to contribute to a rough 110% increase in threat cause, which helps them to pick up a great amount of threat, and manage it much better than the Holy alternate tank path.
Holy Tank, Tankadin (31/20/0)
Holy tanks are very good at grabbing initial agro thanks to consecration and Holy Wrath, which can act like a warrior's taunt, and immediately try and gain snap agro from someone if they manage to steal it from the Tankadin. Holy paladins, using Imp Righteous Fury can have a great chance of gaining agro with Holy Wrath, allowing them to deal a great amount of threat when in order to quickly get their targets.
Holy Tank, Classic Weapon/Shield (2/31/18)
A build which is centered around the image of shield and sword wielding knights. This build relies a lot on the mobs attacking the Paladin to actually hit the Paladin. Improved Aura of Retribution, Blessing of Sanctuary, combined with Holy Shield, and Redoubt give the enemies multiple ways to inflict Holy damage back onto themselves. Combat consists of Judging either to Wisdom or Crusader depending on number of enemies and cycling through Judgements of Command on the enemy. While block with Redoubt and Holy Shield with Blessing of Sanctuary up its possible to do well over 100 points for each hit blocked. Redoubt and Holy Shield combine for a 60% chance to block nearly ensuring the damage will occur. The two points in Holy can be moved elsewhere but are presented as such with 5 points of Benediction as this is a mana using build. Concentrate on Stam/Int gear. The shield being used should bear the best shield spike the Paladin can obtain.
Retribution spec'd Paladins typically fall under the name Critadins, as they attempt to do what many think is an oxymoron: Paladin DPS.
Heavy Ret, Critadin (5/8/38)
This spec's main focus is on the Retribution Tree, although it invests in the early talents of the Holy Tree and Protection Tree to gain both a strength and armor bonus. This build is meant for Paladins who are more interested in dealing damage rather than playing a great role in a group or in PvP. While this build does have its weaknesses, it does make the Paladin have a much greater chance to be a threat on the DPS scales. This build is by far and away a PvP build as nobody wants a Paladin in their raid who is not off-tanking, healing, or both. Paladins should not be DPSing in PvE.
I would however like to add another perspective that perhaps is a more balanced view to the above. Firstly I would have to agree, I don't think there is such a thing as a 'DPS Paladin' but of course they do have a melee role within the PvE setting. My guild during MC and BWL have made use of key melee paladins to exercise their judgements to assist in progression. So yes select Paladins should be used in melee for this purpose. Of course you don't need to be retirubtion specced but it does help in making the most of your melee efforts. As a Retribution Paladin I am still a high performer in heals, cleansing and damage although damage is not really that important for my class in PvE. So, yes I still do play a great role in PvE. Moral here is it doesn't depend on your spec but how good you are in playing your hybrid role in the time you have. I am a Retribtuion Paladin that does melee in a PvE environment and I'm still a high performer in heals and cleasing.
A good Paladin will find themselves busy on any raid if they have a balanced approached to healing, cleansing, blessings, judgements and raid recovery REGARDLESS of your specialisation.