If you're going by position, choosing between Clingan and Okafor is probably the most difficult one. I still think I go with Okafor just based on his quickness off the floor, lateral movement and advanced positional defending. The game has changed such that blocked shots are less frequent, but Okafor's numbers were just silly. But if there's a difference it's minimal.
1st team:
Ricky Moore
Stephon Castle
Nadav Henefeld
Lyman DePriest
Okafor
2nd team:
Boatright
Diarra
Scott Burrell
Donyell (even though he was merely a shot blocker and not great overall defender)
Clingan
Honorable mention:
Napier, Taliek Brown, Thabeet, Voskuhl, Feeman, Josh Boone, Tate George, Brimah