It was a difficult choice between Bettman and Selig, but I went with selig because while both had problems with the unions, leading to a lost season, Selig's absolute failure to face the steroid problem is going to be a permanent taint on the sport long past what Bettman has done. I'm giving Goodell the benefit of the doubt because the NFL hasn't lost its season yet.
As for David Stern, you people are crazy. He's not only the best of the 4, but one of the best commissioners ever in any sport. He might be a jerk, but he took the NBA from a rapidly declining league to the worldwide success it is today.