I think you have to go with Oscar/Kareem, since Magic and Kareem didn't quite coincide at their peaks...but Robertson was past his prime then too....it's really hard.
Basically there are about 6-8 guys you could make a case for as greatest ever; clearly the top 8 in NBA history...Russell, Wilt, Big O, Kareem, Magic, Bird, Jordan, Shaq.
2 duos have 2 of these players: Kareem/Magic, Kareem/Big O; I feel as though one of these therefore must the be the best duo ever.
As for Jordan/Pippen vs Malone/Stockton; I'd say Jordan>>Stockton>=Pippen>Malone, so Jordan/Pippen clearly wins.
that's the sad thing, that great duos can get you a title now; since the 90's pretty much. before then teams had 3 all time greats; who's teh best trio? bird/magic/parish or kareem/magic/worthy?