Since people think I don't know sh*t about DK DPS and how I'm a dirty leecher, I'll contribute what I know. Credit goes to all the people at EJ who devote their time to theorycrafting and number crunching this out. Just note, the rotations listed here aren't iron-cast. That is, learn to adapt to situations. You won't be doing the same "rotation" each and every fight. When adds spawn, switch to the AoE rotation if needed and so forth.
Common Abbreviations
AoE = Area of Effect
AMS = Anti-Magic Shell
BT = Blood Tap
BB = Blood Boil
BCB = Blood Caked Blade
BP = Blood Presence
DC = Death Coil
DCh = Deathchill
DK = Death Knight
DnD = Death and Decay
DPS = Damage per Second
DS = Death Strike
FC = Rune of the Fallen Crusader
FF = Frost Fever
FS = Frost Strike
GCD = Global Cooldown
HB = Howling Blast
HS = Heart Strike
HoW = Horn of Winter
IT = Icy Touch
KM = Killing Machine
NoTD = Night of The Dead
OB = Obliterate
PS = Plague Strike
RP = Runic Power
SS = Scourge Strike
UA = Unbreakable Armor
UB = Unholy Blight
UP = Unholy Presence
VB = Vampiric Blood
Blood DPS
Specs
The only spec is 51/0/20 with a few variants in the spending on Unholy Talents. Blood requires a lot of Armor Penetration to really work.
With Ghoul Glyph and NoTD:
Talent Calculator - World of Warcraft
With Death Strike Glyph and max Morbidity:
Talent Calculator - World of Warcraft
Rotation
1 Rotation
IT PS DS HS HS Dump
HS HS DS HS HS Dump
Alternative with Vengeful Heart Sigil
IT PS DS HS HS Dump
HS HS HS HS HS HS Dump
AoE
IT PS Pest DnD
Start normal rotation
Frost DPS
Specs
There's 3 variants of the accepted 17/51/3 spec. Two which has a glyph change between IT and HB, while the other is the 6xIT experimental spec. There is also the 6xIT 20/51 experimental spec.
17/51/3 with IT Glyph:
Talent Calculator - World of Warcraft
17/51/3 with HB Glyph:
Talent Calculator - World of Warcraft
17/51/3 6xIT spec:
Talent Calculator - World of Warcraft
20/51/0 6xIT spec:
Talent Calculator - World of Warcraft
Rotation
Single Disease (HB Glyph) - BP
HB OB BS BS Dump
OB OB OB
Some info on when to use HB. Credit to EJ forums.
Double Disease Rotation - UPOriginally Posted by Darkside of ElitistJerks
IT PS OB BS BS Dump
OB IT PS IT IT Dump
6xIT Rotation
IT PS OB BS BS Dump
IT IT IT IT IT IT Dump
Use FS during the second rotation when you're about to go over the cap.
AoE
Same as normal rotations but use Pest and HB when needed.
Unholy DPS
Specs
There's 2 main specs for Unholy, with 1 variant new one without much testing.
12/0/59 Blood Unholy Spec:
Talent Calculator - World of Warcraft
0/10/61 Frost Unholy Spec:
Talent Calculator - World of Warcraft
7/10/54 Unholy Spec:
Talent Calculator - World of Warcraft
Rotation
SS(IT PS) BS BS SS Dump
SS SS SS Dump
Replace a SS with a IT PS wherever necessary if your diseases are about to fall off. Use Ghoul Frenzy with a BT after SS but before 2xBS. When BT is down, use the Death Runes to Ghoul Frenzy, use the other Death Rune to cast IT.
Pots, Flasks and Runeforge
Pots: Insane Strength Potion and Indestructible Potion
Flask: Endless Rage
Runeforge: Fallen Crusader for all specs.
Sigils
Blood: Dark Rider, Awareness, Vengeful Heart.
Frost: Frozen Conscience, Awareness, Vengeful Heart.
Unholy: Arthritic Binding, Awareness.
Hit and Expertise Caps
Hit Cap is 8% which is 262 rating
Alliance with Draenei is 7% which is 229 rating.
Spell Hit Cap is 17%. DKs get 3% from Virulence lowering it to 13%. Add in 3% from Misery or Improved Faerie Fire and that's 10%. Add in another 1% for Draenei and thats 9%.
Horde: 262 Hit Rating
Alliance: 232 Rating.
Expertise Soft Cap for no dodges is 6.5% = 26 Expertise = 214 Rating.