Hands down Goku all the way, don't get me wrong I'm a huge fan of Naruto and Luffy. But Goku has 4 levels of super saiyan under his disposal, Gary Girth has nothing on Goku! But it would be interesting to watch it in display.
Gary Motherfucking Oak! He doesn't even need to raise his hands to wipe the floor with everyone else; they would just lose the will to fight after being in the presence of his girth.
All of you guys are forgetting, this isn't an actual battle. They can't use any of their techniques they've learned (naruto's Justsu, Luffy's Haki, or Goku's Super-Saiyan-ness) this is just a regular old bar brawl.