Preferred Gengar moves?

[Chig]

I want to make a good gengar, but I dont know what moves I should get. What are the preferred moves that makes Gengar popular? 

[DiosSlurpuff]

I will leave you the most common sets, although the most viewed is the first

 

Sub nplot:

Gengar @ Black Sludge  
Ability: Cursed Body  
EVs: 4 HP / 252 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Shadow Ball  
- Focus Blast  
- Substitute  
- Nasty Plot  

 

 

Sub Disable:

Gengar @ Black Sludge  
Ability: Cursed Body  
EVs: 4 Def / 252 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Shadow Ball  
- Focus Blast  
- Substitute  
- Disable  

 

 

Sub Pain Split:

Gengar @ Black Sludge  
Ability: Cursed Body  
EVs: 4 Def / 252 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Shadow Ball  
- Focus Blast  
- Substitute  
- Pain Split

 

Choice :

Gengar @ Choice Scarf/Specs 
Ability: Cursed Body  
EVs: 4 Def / 252 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Shadow Ball  
- Focus Blast  
- Energy Ball /Thunderbolt/Psychic/Icy Wind/HP Fire
- Trick  

 

Bulky WoW:

Gengar @ Black Sludge  
Ability: Cursed Body  
EVs: 252 HP / 4 Def / 252 Spe  
Serious Nature  
IVs: 0 Atk  
- Shadow Ball  
- Focus Blast  
- Substitute  
- Will-O-Wisp