I would probably go something like this:
PG - Magic Johnson, Gary Payton
SG - Michael Jordan, Kobe Bryant,
SF - Larry Bird, Elgin Baylor, Scottie Pippen
PF - Tim Ducan, Kevin Garnett, Karl Malone
C - Kareem Abdul Jabar, Hakeem Olijuwan
Reasoning:
Magic - Because he's Magic. Payton - Not only a great outside shooter but a great rebounder, assist man and the best defensive PG ever IMO.
MJ - Because he's MJ. Bryant - The closest thing anybody has ever seen to MJ at the 2 guard. Some say that he might be better (but I don't agree). Bird - No athletic ability at all but simply the best shooter I've ever seen. Maybe the smartest player I've ever seen. Baylor - He could do it all. Shoot the ball, rebound, play defense, pass, run the floor and create off the dribble. Best all around SF in the history of the game IMO. Pippen - A great player, could run the floor and finish, could rebound and pass but he's here because he is probably the best Defensive SF worthy of being here. (Actually, I thought James Worthy was more dangerous but not as good defensively and we needed defense more then we needed the rest). Duncan - Do it all PF that could play the post as well. Highly intelligent player and money when the game is on the line. Garnett - Defensive, Rebounding fool that can also give you offense in the post. He's the stopper at PF. Malone - He's the Mailman. He matches up with the smaller, more mobile PF you often see. Plus, Rain or Shine, he gets it done on the offensive side of the court. Kareem - Unstoppable offensively, dominating defensively plus he could pass as well as any big man ever and he could shoot FTs at crunch time. Unstoppable in post. Olijuwan - Mobile, shoot blocking, rebounding machine that could run the floor and finish. Also had an unstoppable turnaround jumper from anywhere on the court. The best true defensive Center I've ever seen. Better then Ewing and better then Russell IMO.
Not everybody on this list might be considered the best at their respective positions but for every position, I included somebody who did have an exceptional game but was the best defensive player at their position as well. I sacrificed offense for defense in some situations basically.