1. The 2015-16 San Antonio Spurs
Of all of the great Spurs teams, it's hard to argue that the 2015-16 team wasn't the most talented. After all, it had most of the rotation players from the 2014 title team but featured a much-improved Leonard plus new additions like David West and LaMarcus Aldridge.
The team breezed through the regular season by slowing the game down and relying on a highly efficient offense and elite defense. As a result, the Spurs won a franchise-record 67 games, went 40-1 at home, and looked like they were on a collision course with a 73-win Golden State Warriors. Unfortunately, that potentially epic series didn’t happen.
Instead, the Spurs were upset in the second round by their rivals, the Thunder. The Thunder, to their credit, nearly beat the Warriors in the West Finals, making the Spurs' loss look better. Still, it's disappointing that the best Spurs team ever, record-wise, lost so early on in the playoffs.
All in all, while the Spurs have won five championships, they’ve had at least as many great teams that didn’t win a title. However, only a handful of teams have won as many championships as the Spurs, proving that they're one of the best franchises in NBA history.