Tank suggestions?

[DestroyerOfLargePlanets]

Warrior: Huge HP pool. Damage mitigation is a lot harder for WAR than for DRK or PLD, since their mitigation requires more planning. (Storm's Path debuff and Inner Beast, not to mention the lack of built-in damage reduction from their tank stance). Their invulnerability move (Holmgang) is only 6 seconds (it's not THAT great, but top-tier players often abuse this move by using it to completely ignore a tank buster while they DPS) but it does have a lower cooldown than DRK or PLD's invuln. It also roots them in place. WAR has huge DPS capabilities though. WAR can apply a slash debuff (Storm's Eye) which decreases an enemy's slash resistance by 10%, and they can also apply another debuff (Storm's Path) that decreases an enemy's damage by 10%). WAR is a staple in most raid groups because they can dish out lots of damage while also being able to debuff the boss with those valuable debuffs. WARs often fill the offtank role, where the main tank tries to hold the boss as long as possible to increase a WAR's DPS uptime.

Dark Knight: Less HP than WAR. Same HP as PLD. Mitigation is pretty easy. Just pop a cooldown or more if it's up. They're good against magic damage since they can apply a debuff that decreases an enemy's intelligence (magic damage dealt) and they have Dark Mind -- a defensive cooldown which can negate up to 30% of incoming magic damage to the DRK which is HUGE. Their invulnerability move (Living Dead) for simplicity's sake forces the healer to spam focus heal the DRK or else he dies, though Living Dead does technically give the DRK a 10 second invulnerability. Slightly higher damage capability than PLD, but is still outshined by WAR. DRK fills the main tank role, but can still dish out a decent amount of damage compared to PLD. DRK also has the move Plunge, which allows the DRK to jump to an enemy. DRKs have to manage their MP, as they are a mana-based class.

Paladin: Same HP as DRK. Tanky as all hell due to their shield's block potential. Their invulnerability is straight up 10 seconds of no damage, whereas DRK's invuln gives healers a heart attack if the healers aren't raid-level. This allows PLD to cheese certain mechanics and spoil the offtank rotten. Damage is less than that of DRK. Paladins have the spell Clemency, which is a nuke heal, and they also have Divine Veil, which shields the party for 10% of the PLD's max HP.