Update: Here's a starting point for general information from this thread. A large portion of this came from bucknasty here.
Death Knight tanks are the fourth and newest tanking class to be created in World of Warcraft. Death knight tanking shares qualities with all of the other tanking styles and has some of its own flavor to bring into the tanking pool. The biggest difference is the lack of a shield. To compensate for this lack of armor, Death Knights have a Frost presence, not unlike a druidâ€™s bear form, that increases the armor gained from items.
Death Knights have two taunts, Dark Command (8 second cooldown) and Death Grip (35 second cooldown untalented). Death Knights do not have an AOE taunt.
One of the strengths of Death Knight tanks is their ability to maintain significant AOE threat levels. There are 5 main AOE tanking abilities at our disposal:
Death and Decay
Howling Blast (31 point Frost Talent)
Corpse Explosion (11 point Unholy Talent)
Unholy Blight (51 point Unholy Talent)
2h vs DW
There are no dual-wielding specs that generate comparable threat to 2-hand tanking while retaining other essential tanking talents. There are also serious parry-hasting concerns that currently render DW tanking inferior to 2H tanking. This is subject to further study of course.
It is currently generally accepted that for raid-level main tanking Death Knights have a choice between creating a Frost build or an Unholy build. Both have their strengths and weaknesses, but both are fully capable of main tanking. There has not been significant theorycrafting to decide if a similar Blood spec could be put together to perform on par for main tanking. That being said, due to the wonderfulness of Frost Presence nearly any Death Knight build should be able to off tank in emergencies and in 5-man instances (assuming they have tanking gear in their bags).
Of note, for all of these builds there are many variations that a player could make to better fit their play style, the needs of their raid, and other circumstances.
There are two primary Frost build variations. The first includes Imp Icy Talons, the second skips it. The idea being, if you are raiding you will have a Windfury totem, which Imp Icy Talons does not stack with.
With Imp Icy Talons
Without Imp Icy Talons
For the build w/o Imp Icy Talons there will be significant variation in the first half of the tree due to the lack of obvious replacement talents for Imp Icy Talons. Killing Machine is typically an increase in threat compared to Imp Icy Talons (assuming WF is present), but feels lackluster for 5 points. Other options are Icy Reach to help with pulling or Merciless Combat for increased threat/DPS at the end of fights. Another area of variation will be whether or not to get Acclimation, it can be good, but it is not clear if it will stack with resist totems/auras and it is not useful on non-caster bosses.
Frost aura's contribution is debatable and some argue "better" places to put the points.
Hungering cold is highly situational at best and is largely considered a PvP talent. In my personal tanking experience I would never use it, as I haven't encountered single (or multiple even) packs where the damage incoming was too high. I've always preferred AOE to just burn everything down, and I've had the threat to allow (encourage) this.
Unholy tanking is often considered an equivalent to Frost tanking the moment your bone shield can stay up for 20 seconds on average. This is obviously highly dependent on avoidance gained from gear, and is sometimes considered inferior to frost tanking for heroic/early-Naxx tanking. Bone shield is least effective when taking smaller amounts of damage at frequent intervals, particularly magic damage, as the charges will diminish quickly. It is currently believed that Bone Shield has a hidden 3.5 seconds cool down on bone-loss.
Generalize builds forthcoming
Things to Avoid
In general, any talents that are chance on auto-attack should be avoided if better options are available. This is due to the fact that many white-hits end up being converted to Rune Strikes, which can not proc these talents. This is the reason Killing Machine is such a lackluster talent for tanking. There may be an exception to this generalization if Dual Wield tanking ever becomes viable (since it would include many more white-hits).
Available tanking glyphs:
- Glyph of Icy Touch â€“ The increased RP generated from this glyph is very useful. Rune strike, frost strike and death coil are all great abilities, and any extra RP is useful. Many other abilities require RP, including Anti-Magic Shield and Icebound Fortitude.
- Glyph of Bone Shield â€“ A must for Unholy tanks.
- Glyph of Dark Command â€“ A must for any tank. Having a taunt miss is obviously problematic and reducing eliminating this chance is essential.
- Glyph of Obliterateâ€“ Obliterate is the bread-and-butter ability for Frost tanking and this glyph buffs it once a certain average weapon swing damage has been reached. The exact number is yet undefined.
- Glyph of Rune Strike â€“ Increases cost by 25% for a 20% increase in damage. Very useful if you find you have more RP than you know what to do with.
- Glyph of Death and Decay â€“ Decent glyph for reducing incoming damage while AOE tanking or PvP fun.
- Glyph of Icebound Fortitude â€“ Making shield wall free is never a bad idea.
- Glyph of Death Grip â€“ This one is largely a PvP glyph. It has very limited raiding use.
- Glyph of Pestilence â€“ This is an amazing glyph for all DKâ€™s. Use this one.
- Glyph of Horn of Winter â€“ Not a bad glyph. It allows you to Death and Decay the use Horn of winter before entering combat (it is possible without this glyph).
- Glyph of Corpse Explosion â€“ gives you the chance at an extra explosion for each use of the spell. Not great, but there arenâ€™t a lot of minor tanking glyphs, and I needed to add a third.