80's. Most of the greatest players in NBA history, whether at their peak, declining, or upcoming, played in this decade.
The 80's was, of course, the era of Bird, Magic, Isiah, Moses, Dominique who were the top dogs at that time, as well as talented players like James Worthy, Kevin McHale, Bernard King, the troublesome Micheal Ray Richardson, Adrian Dantley, Alex English, Clyde Drexler, Sydney Moncrief, Mark Aguirre, Tom Chambers, among others. But the 70's greats, e.g. Kareem, Dr. J, George Gervin, David Thompson and Artis Gilmore, were still there and competing at the top level. Then came the batch that would dominate the 90's led by Michael Jordan, Hakeem, Barkley, John Stockton, Karl Malone and Patrick Ewing. In short, this decade saw the fusion of 3 eras so it just teemed with incredible talent.