luffy would win i think its pretty obvious cuz he simply can't die.
goku would show us an hell of a fight but would die, train while death, resurected and then win.
gary oak ...... ok he would give a few douche sentences and then die.
naruto well yeah would be a hard one on luffy
but he would die before the battle durin an contest dining with luffy
did any one even see the term "fist fight" it means goku not using a spirit bomb or kamehameha. and it means naruto not using a rasengan, and luffy not using any of his gomu gomu techniques. by default luffy already wins as his rubber body won't take any damage