Edit: Updated for Cataclsym: This guide will obviously become invalid when the Cata patch 4.n.n patch launches and changes all the talent trees. For anyone who doesn't know yet, neither Frost nor UH will be able to tank in Cata, only Blood.
Edit: Updated for 3.3.3. Endless Winter now a required talent, example builds updated.
Blood and Frost are both tight, and at some point in your DK career it will behoove you to familiarize yourself with tanking in all three trees. DK's are the only tank class that can tank with more than one tree, and sometimes one is stronger than others depending on certain content and Blizzards nerf/buff whims.
But right now Frost is strongest for 5mans. Its easy AoE & AoE disease-application, strong single and multi-target threat, built-in passive mitigation and avoidance enable the fastest, most aggressive DK tanking style possible for 5mans, necessary when LFG farming w/ trigger-happy aoe-spamming dps.
(Blood is better for raid boss tanking right now, due mainly to higher EH, but scales better at higher gear and stamina levels than someone just starting the 5man grind.)
Start with this standard 15/51/5 build (or 13/53/5 for DW Frost, moving pts b/t Killing Machine and Scent of Blood to suit your taste), then experiment as you get used to it.
Required Talents:
- 5/5 Blade Barrier, 5/5 Toughness, 5/5 Anticipation (avoidance & mitigation)
- 5/5 Bladed Armor (significant AP buff in Frost Presence, point-for-point one of DK tank's best threat talents)
- 3/3 Improved Icy Touch (reduces rate of incoming physical dmg, helps healers keep up)
- 5/5 Black Ice (threat)
- 3/3 Annihilation (threat, and Frost's main nuke Oblit doesn't clear diseases)
- 5/5 Killing Machine (another amazing threat talent, both AoE and single target)
- 2/2 Chill of the Grave (Frost is RP-starved, need it for Rune Strike, Frost Strike, IBF, and AMS)
- 3/3 Glacier Rot (threat)
- 2/2 Endless Winter (threat)
- 3/3 Frigid Dreadplate (avoidance)
- 2/2 Improved Frost Presence (mitigation)
- 3/3 Blood of the North (threat & death runes)
- 1/1 Unbreakable Armor (good tank cd post 3.2.2, esp glyphed)
- 1/1 Frost Strike (RP dump, death coil sux in Frost)
- 3/3 Guile of Gorefiend (threat, and increased IBF duration)
- 5/5 Tundra Stalker (threat, expertise)
- 1/1 Howling Blast (primary AoE)
The objective with several of the required talents is to max Howling Blast AoE damage and threat. Namely, Bladed Armor + Black Ice + Glacier Rot + Tundra Stalker + Killing Machine + Endless Winter + Guile of Gorefiend + Rime. The synergy among those talents also buffs DnD and Blood Boil AoE as well.
Optional talents:
- 3/3 Scent of Blood (I personally consider this mandatory, I like max RP regen for FS spam. Others don't. Very low internal cd, especially good w/ faster hitting DW spec.)
- 2/2 2H Weapon Specialization (Most consider this mandatory for 2H tanking, as do I, a few don't)
- Lichborne (useful on a few fights, like Paletress, King Dred; fills the gap b/t AMS cd's; 2m cd.)
- Deathchill (nice way to start AoE pulls, with a guaranteed HB crit. 2m cd, useful roughly every third or fourth pull)
- Hungering Cold (spell interupt, applies FF, but 40RP requirement means good chance it won't be up when needed, so requires the glyph. Quick 1m cd. Useful way to start pulls so your subsequent HB benefits from FF on all mobs, decent oh-shit snare as long as no AoE on the ground breaks it)
- Merciless Combat (increased threat during burn/enrage phase; filler to open rest of Frost tree)
- Chilblains (More of a pvp talent, some may find it situationally useful)
- Acclimation (useful on fights w/ constant spell dmg (Sapphiron, Garfrost), not worth it in an all-purpose build)
- Improved Icy Talons (nice group buff, but haste is DK tank's least useful stat, and opportunity cost maybe too high. An example build. Ideally you want a Shamman w/ Windfury Totem, or a Frost DPS DK to provide that buff.)
- Virulence (if your hit rating is too low relative to mob level, your taunts will miss. Virulence can help with that till you get enough hit from gear/gems, then move those points to something better. Also consider Glyph of Dark Command for raid fights w/ lots of taunting (Gormok, and like half the ICC bosses). And nothing in PvE dispels, the dispel resistance is for PvP only.)
- Unholy Command (has 2 effects, grip and temporary taunt that forces mobs to attack you for 3s. Many mobs are immune to the grip effect, but not the taunt effect. Useful in a pinch if Dark Command is down or gets resisted)
- Morbidity (I personally consider this redundant and unneccesary, since Frost already has such strong AoE, and you should be using Frost Strike as the RP dump not DC. But others like the reduced DnD cd, so you'll have to experiment w/ it and see for yourself)
Unnecessary, redundant talents:
- Epidemic (base disease duration 15s, Frost Fever refreshed every 8s w/ Glyphed HB, faster w/ Rime procs)
- Subversion (useful crit buff on Oblit, but there are better places for those points)
- Runic Power Mastery (you should be spamming FS and RS so much you never hit the 100RP cap, much less 130RP cap)
- Icy Reach (all mobs should be on you, not out of range. Tuskar's Vitality on the boots as tanks w/out Charge or increased mobility should, plus Dark Command taunt, Strangulate, and Death Grip for ranged mob control)
Required Glyphs
- Howling Blast (easy AoE and disease application)
Optional Glyphs
- Obliterate for more single-target threat (this one is so strong it should almost be under Required Glyphs. Unless you're really having trouble w/ AoE threat, this should be your second Glyph after HB).
- Frost Strike for more single-target threat
- Rune Strike for more single-target threat (though this is better for MT'ing a raid boss for several minutes straight than the quick pulls and short fights in 5mans; I prefer 1 or 2 for single-target threat in 5mans)
- Icy Touch for more AoE threat
- Unbreakable Armor for more mitigation (and threat from both the +Strength and Bladed Armor)
- Hungering Cold essentially necessary if you spec Hungering Cold
- Death and Decay if you are really having trouble w/ AoE threat
Whether you need more single-target threat, aoe threat, or mitigation will depend on your gear relative to both the instance and the dps in your group. You'll have to experiment w/ which combination of glyphs works best for you in that respect. Keep in mind you can carry stacks of all these glyphs in your bags, and change them out inside the instance or raid as the situation dictates.
AoE rotation:
- initial: DnD + HB + BB + FS dump
- subsequent: HB/OB + HB/OB + BB + BB + FS dump (spam HB and BB as much as possible, use OB when HB on cd to get Rime procs (Freezing Fog)
You can skip plague strike and blood plague on AoE fights. Oblit and BS lose a little extra dmg from the lack of Blood Plague, but Glacier Rot and Tundra Stalker more than compensate and only require FF, not BP. Use PS/BP on Single-target fights though.
Single target rotation:
- initial: IT + PS + Oblit + BS + BS + FS dump
- subsequent: Oblit + Oblit + BS + BS + FS dump (HB when Rime procs Freezing Fog)
Oblit, HB, and IT+PS each use same runes, so interchange as needed. Same w/ BS and BB.
Additionally, keep in mind your initial stat goals for tanking:
535 Defense (uncrittable by lvl 82 boss). 540 for raids (unrittable by lvl 83 boss).
26 Expertise (elminates lvl 83 boss parries and dodges of your special strikes, reduces parries and dodges of your autoattacks. 26 exp per hand if DW'ing.)
264 hit rating / 8% hit chance (eliminate special strike misses vs.
lvl 83 boss, and reduce taunt misses).
The Hit and Expertise are needed for threat gen (missed, dodged, parried strikes = no threat), and Expertise provides some extra avoidance and dmg reduction (less parry-hasted boss attacks).
Hit also reduces the chance your Taunt will miss, though 17% spell hit (calculated from hit rating differently than melee hit) is required to completely eliminate Taunt misses. However, at high enough gear levels you can trade the hit cap for additional stamina without losing much threat (since a large portion of our threat comes from unmissable Rune Strike), but on fights that require constant taunting (Gormok, Toravon, and about half the ICC bosses) you may need Glyph of Dark Command compensate for the increased chance to miss taunts.
After getting those stats, stack stamina, dodge, and/or defense. Check out Tankspot's Guides for more on gearing, gemming, and enchanting.
Finally, the frost build I linked is a good, self-sufficient, starter build for learning the style and pugging 5mans. However there are some talents that other classes can provide. For example, if you find yourself running a lot with a Resto druid with Revitalize, you can switch out Scent of Blood and/or Chill of the Grave for something else, like Acclimation or the Improved Icy Talons melee haste raid buff.
Other classes provide other such buffs. Just one thing to keep in mind as you get more experience with it, join a guild, and start raiding with the same people regularly. At that point you'll want to take a look at all the classes you raid with and see what synergies are available, and get everyone to consider respec'ing accordingly.
Edit: A few useful links for DK tanking.