Raito Nakamura
It always depends... Supermans powers are connected to the sun, if they would battle in space for example, at some point supermans batteries would run low...
Gokus power comes from within... would only be funny if he would transform into a super sayan and Superman would power up with the light of his aura
xd
I don't think their powers are equal though, I would root for Goku because he is so retardedly overpowered that he can easily blow up planets (yes probably more than one, because they were already able to do that at the frieza saga and they got a lot stronger in the end, so how else to top that?)... Superman can throw a punch, but he can't really keep up with Gokus Kame hame Ha, the only thing comparable he has is his heat vision, but I don't think that can be equally strong. If they decide to have only a fist fight, it would be hard to tell, but if they really have an all out fight with all their abilities, Goku would most likely win.
If Superman can survive Darkseid's Omega Beams, he can survive the Kamehameha and Superman being Superman would make the Spirit Bomb ineffective since it doesn't affect people of pure heart.
Also Superman can hold his breath for a pretty long time and his Kryptonian cells are capable of holding onto
a lot of yellow solar energy for quite a long time. If they were to fight in the cold vacuum of space, Goku wouldn't exactly last. He had a plot shield on the last time (and only time) he was in space.