In my opinion it's the player that can play in any team in the world and be the difference! Messi , Ronaldo are world class players and they have never been in a World cup finals ! Suarez is close to being it probably, no yet, but getting there !
the world world class is branded around far too much these days. as some people have said a worldclass player for me is someone that would walk into any/most teams in the world ( club or country) this are some player that think are world class
* messi ( no real surprise there )
* ronaldo
* iniesta
* falco
these are players that are branded as worldclass but IMO aint
* rooney
* terry
* rio ( even at his peak)
* fabregas
* villa