If you are going to play Diablo 3, then you will be interested to see our new website DiabloProgress.
DiabloProgress will be fully launched shortly after Diablo 3 release. It will include progression ranking, leveling ranking, gear rankings and many other features!
Based on information from developer interviews, Inferno mode is going to be really hard and there will be no official ladder. DiabloProgress probably will be your primary source about all the progression data and statistics for the game.