Those who picked Floyd-Cotto are unfortunately very wrong. Mayweather is a superstar but Cotto is still the hardcore fan's star. Biggest fight would be: DLH-Mayweahter II by far (the average HBO viewer would buy this after 2 months of the Mayweather Family brainwash), DLH-Hatton, DLH-Tito (hell, he did 510k vs. Roy), DLH-PacMan and PacMan-Hatton in that order.
I think that in 8-12 months Klitscho vs Haye might fast become the biggest event in boxing. If both do what they're supposed to do, and this is billed as THE superfight of the heavyweights - there is a marketing potential, and if promoted right, a legacy/historical potential, to be one of the biggest heavyweight fights in a long long time.
Cotto vs Mayweather was the biggest fight to be made, but now that Mayweather is retired, it's probably Pacquiao vs Hatton.. I don't think the average boxing fan would know who Pavlik or Calzaghe really is.. Maybe seen them in the JT & BHop fights, but that's just about it maybe..
I don't know about you all but I am very surprised that Cotto vs PBF it's the number 1 choice and that a second choice is PAC vs Hatton!