Megaman rocks!
At a post-Christmas toy clearance, I saw the Rock 'Em Sock 'Em Robots game, which enjoyed a brief revival a year or so ago. Since I didn't have this game as a kid, when it first came out, I was surprised to see the robots are called the Red Rocker and the Blue Bomber. So that's where the nickname for Megaman came from!!
... and great, now I have this image of X fighting Sigma and their heads going SPROING like within that game.