Chick Hearn, Vin Scully, Al Michaels, Marv Albert, Jon Miller, John Sterling, Hubie Brown, Howard Cosell
Best duo: John Madden and Pat Summerall
I want to add that Joe Torre was an excellent color commentator before he became a manager. Sometimes I'll leave Dodgers, Giants, and Yankees games on just to listen to Vin Scully, Jon Miller, or John Sterling and I did that with John Madden and Pat Summerall as well, oftentimes they're much more interesting than the games.