Best player to never become world champion ever!

that's a ridiculous statement that can't possibly be true. you don't get to be within the top 3 in the world in something without having some kind of natural predisposition for it. it's just not possible. studying/training in chess can bring most everyone to at least 2200-2300. anything above this is probably due to something more than just study/training alone. Korchnoi was a super gm of his time rated above 2600. of course his name tops this list and he should have won that first match.

all of the above, and Bent Larsen. 

Spassky was known as a gentleman but even gentlemen can act like jerks sometimes. Korchnoi, on the other hand, wasn't liked by many and had few friends, among them Bronstein, who was punished by the Soviets for assisting Korchnoi in the matches with Karpov. I'm reading about Korchnoi now and--gruff and perhaps unlikebale personality aside--- he was almost certainly the highest performing modern supergrandmaster to never win the world championship. 

Magna Carl

Chigorin, Morphy, and Khalifman

Khalifman was world champion

qoute from wiki:

Bent Larsen a candidate for the World Chess Championship on four occasions, reaching the semi final three times. He had multiple wins over all seven World Champions who held the title from 1948 to 1985: Mikhail Botvinnik, Vasily Smyslov, Mikhail Tal, Tigran Petrosian, Boris Spassky, Bobby Fischer, and Anatoly Karpov.

that should make him a candidate, at least mentioned.

Borislav Ivanov. Uh, I mean the great Shoedini.

does Morphy count the forum says while the title existed.

and the title was first official 1886 and Morphy died 1884.

hmm..no AKiba Rubinstein?

Hikaru Nakamura!

Lol yes, his endgameskills with K,N,B against K are legendary, and certainly worthy of a world champ ...

Me

Not any one on this site!