What are the best moves for haunter?

In my opinion, you should Evolve it to gengar and then give it

Shadowball
Psychic
Brick break
Thunderbolt

Shadow ball to counter psychic and ghost types
Psychic to counter fighting and poison types
Brick break to counter dark,rock,steel and normal types
Thunderbolt - addtional attakc. Quite usefull for normal + flying types.

Try:

Shadow Ball
Hipnoices "Spelling" "it puts your foe to sleep"
Dream Eater
Physic.

Depends on who you are. My Gengar's attacks are:
Psychic
Thunderbolt
Shadow Ball
Sludge Bomb

And a lot of people liked it when you were allowed to post your team on the Q/A pages.

The best moves are
Psychic
Thunderbolt
Shadow Ball
Sludge Bomb

Well, in my opinion, the moves that I use would be Hypnosis, DreamEater, ShadowBall/ShadowPunch, and 1 more of your choice.
Use DreamEater instead of Psychic because Psychic has only 90 power, whereas DreamEater has 100 power. DreamEater can also absorb half the damage it inflicted on a sleeping Pokemon whereas Psychic may lower the foe's SP. Attack.
For DreamEater to work, your foe needs to be asleep. Use Hypnosis to make it asleep.
You can choose between ShadowBall and ShadowPunch. ShadowBall's 80 power, ShadowPunch's 60 power but has infinite accuracy.
For the last move, I have no recommendations but if you wish, you could have either Psychic/ShadowBalll(if you chose ShadowPunch)/ShadowPunch(if you chose ShadowBall).

I hope this helps

- RodallDemoJuhziz