Although this poll is already closed and over, I am going to offer my opinion anyway. Although I do not watch Soccer, I am going to vote for Munich.
Like already said in this thread, Mayweather's wins were over the course of his career while the others were just one season. So that is why I rule him out. Now for Peyton Manning and Calvin Johnson. While what they did was impressive, they are doing it in a league that is now dominated by the passing game, both on teams who in my opinion have virtually no run game. Detroit ranked in the lower half of the league for rushing yards this season, and Denver was just a couple spots above them. I am sure Drew Brees or Aaron Rodgers could also throw for 50+ touchdowns if they threw the ball the entire game. Not to mention that the Lions' starting running back is Reggie Bush, a guy who is more fit to be a wide receiver rather than a back. Plus Peyton Manning's offense is stacked to the sky with players like D. Thomas, Wes Welker, Eric Decker, and Julius Thomas.
Because of how stacked the Denver offense was to me, I would put Megatron above Peyton Manning. Just because Calvin Johnson truly is an MVP to me, while I think the Broncos could do just as good without Manning as their QB. They won the division and made it past the wild card the year before Manning came there, and that was with Timmy Tebow as the QB, a guy who is clearly persona non grata in the NFL. Without C. Johnson I cannot see the Lions even coming close to what they do with him.
That is why the most impressive to me is what Munich did. Breaking or tying 30 records is extremely impressive. That not only shows that they have good players, but it shows that they are a good team. The other three to me are more personal. Yeah Manning and Johnson needed someone to catch and throw the ball to them, but still when it comes down to it what they did was more personal than team. While Munich it wasn't just one person doing all the work, it was the entire team and coaching staff in general and that is what makes it so impressive as a whole.