Wilt Chamberlain's 1966-67 Sixers take the cake. That team featured Chet Walker, Lucious Jackson, Hal Greer, Billy Cunningham etc. That Sixers squad is at the top of Rosen's list of the 13 best teams ever.
My thought: if you're going to go that far into history to pick the best team ever (despite plenty of evidence that athletes are bigger, stronger, and more committed to defense today) well then you probably ought to go with one of Bill Russell's teams. The Celtics had the whole league terrified of them for more than a decade, and remain the standard by which all other teams are judged. And, in case it needs pointing out, all other teams are judged poorly in the face of Russell's 11 championships.