It is worth noting that critical strike becomes slightly better in dungeons.
Critical Strike: Death Knights best offensive stat, but one of the worst defensively, only beating mastery.
Haste: Increases attack speed and more importantly rune regeneration. The more haste you have, the better versatility becomes, but the more haste you have the smoother and quicker the spec will be.
Versatility: Quickly becomes your best stat, by giving you a lot of damage & healing done, while decreasing the damage you take.
Mastery (Mastery: Blood Shield): The Blood shield is very minimal and its therefore not worth picking up mastery at all.
Pick whatever race you prefer, It will not change anything for you.
Weapons: Rune of the Fallen Crusader
Strength: 1x Leviathan's Eye of Strength
Versatility: Versatile Dark Opal
Do not forget to use Abyssal Healing Potion!