Most people will name the "Fake Spike" game as one of their favorites and it's certainly one of my personal favorites as well.
The absolute worst for me was Marino's last game when we were embarassed in the playoffs by Jacksonville. Also, the "Monday Night Miracle" against the Jets. You just kept waiting and waiting for the Dolphins to close the door and it never happened.
Best win ever for me?
September 9th, 1984. First home game of the season against New England. We were in the Orange Bowl. My very first Dolphins game....and it was my birthday. Dolphins won 28-7.