Here are some examples of some good Death Knight class macros:
General Death Knight:
#showtooltip<br />/cast [@mouseover, exists] [] Strangulate <br />/cast [@mouseover, exists] [] Mind Freeze
Casts "Strangulate" on a mouseovered target, if it exists, otheriwise it casts Strangulate on the current target
Same for the second line, only with "Mind Freeze". If "Strangulate" is down, it will cast "Mind Freeze".
/cast [nomod] Mind Freeze<br />/cast [mod:shift] Strangulate
Casts "Mind Freeze" when no modifier is pushed, casts "Strangulate" when [shift] is held down
#showtooltip<br />#show<br />/cast Lichborne<br />/cast [@player] Death Coil<br />
Casts "Lichborne" and then casts "Death Coil" on the player (self) when spammed.
#showtooltip<br />#show<br />/castsequence Raise Dead, Death Pact<br />
Click once to cast "Raise Dead", click again to cast "Death Pact".
#showtooltip<br />/cast [@mouseover,harm,nodead] [] Chains of Ice<br />
Casts "Chains of Ice" on your mouseovered target, if you have one, if not, it casts on your current target.
#showtooltip<br />/cast [@mouseover,harm,nodead] [@focus,harm,nodead] [] Death Grip<br />Casts "Death Grip" at your mouseovered target, if you have one, if not, it casts on your focus target, if you have one,<br />if not, then it casts on your current target.
Blood:
#showtooltip Vampiric Blood<br />/cast Blood Tap<br />/cast Vampiric Blood
Casts "Blood Tap", and casts "Vampiric Blood".
#showtooltip<br />#show<br />/castsequence reset=target Icy Touch, Plague Strike
Casts "Icy Touch" first, then "Plague Strik"e. The macro resets when you switch targets.
#showtooltip Icebound Fortitude<br />/use 13<br />/use 14<br />/cast Icebound Fortitude
Uses any "use" trinkets you may have, then casts "Icebound Fortitude".
Unholy:
/cast [mod:shift,@pet] Death Coil<br />/cast [nomod] Death Coil
If holding down [shift] this will heal your pet, otherwise it will use as usual.
Frost:
#showtooltip<br />#show<br />/castsequence reset=target Howling Blast, Plague Strike
Casts "Holwing Blast" and then "Plague Strike". The macro resets when you switch targets. Notice that this isn't very good if you're trying to AOE down mobs.
#showtooltip Pillar of Frost<br />/use 13<br />/use 14<br />/cast Pillar of Frost