Kevin Pelton of ESPN Insider joins Nate Duncan to discuss the greatest teams of all-time, including the 60s Celtics, '71 Bucks, '72 Lakers, '83 Sixers, 80s Celtics and Lakers, 90s Bulls, and the best recent teams. They also got into changes in style of play and the relative strength of the league through the years, then pick their personal top-fives.