Obviously Mayweather vs Pacquiao, it will determine who the best p4p fighter since Whitaker is & its been 2 years overdue. This would be like asking in 1993 `Do you want Whitaker vs Norris or Whitaker vs Chavez ?` The obvious answer is & should be Whitaker vs Chavez because that is a battle to decide who is p4p no1.
Of course Pacman vs Mayweather. They are similar in size and no catchweight would be needed. Martinez would be weight drained at 150 and would be a shadow of himself if he fought either fighter. kudos to him showing the willingness to do that but it would take away a lot from the fight.