Bobby Clarke vs. Bobby Orr. Julius Erving vs. Larry Bird. Donovan McNabb vs. Tom Brady. Philadelphia and Boston share a long and storied playoff history and the two cities will renew another when the Flyers and Bruins face off in the Eastern Conference Semifinals beginning Saturday afternoon at TD Garden. The two teams have not met in the post-season since the 1978 Stanley Cup Semifinals when the Bruins defeated the Flyers in five games, four years after the Flyers upset the Bruins in the 1974 Stanley Cup Finals. After six days of waiting for a second-round playoff opponent, the Flyers finally learned it will be the Bruins when the eighth-seeded Montreal Canadiens stunned the top-seeded Washington Capitals 2-1 in Game 7 Wednesday night. The Canadiens will take on the fourth-seeded Pittsburgh Penguins in the other conference semifinal.