A simple HUD for the 3 important Vengeful Spirit (Ghost form at Teron Gorefiend) Skills at the middle of your Screen, right underneath your Character. Shows Spell, Cooldown etc.
I recommend combining those 3 important spells into your Macros, their correct Names would be:
/cast Spirit Chains (AoE Root)
/cast Spirit Volley (AoE Damage)
/cast Spirit Lance (Singletarget Damage + Slow)
Cheers and good luck.