Goku for sure.The very thought of superman brings along with it the fact dat how since years kids have been going through the same character as outlined by different cartoonists while "Goku' brings along the thought of how well can a character be portrayed by mere imagination, leaving behind with it a significant impression on the minds of viewers. It wouldn't be wrong to say that "Goku" has been successful in leaving its deep imprint on the fresh and creative minds of teens. Goku in itself reveals the success of animators in influencing, alluring, entertaining and dumbfounding the young generation.
You argue of dumbfounding the young generation yet you use "dat"? Anyways, Goku is just as superman. I grew up with Goku. I had Goku toys and pajamas. Goku is just as much as an icon for people of all ages. This was also more of less of who would win in a fight. Which, of course, Goku would. Superman is strong yes, but would only be able to stand against Goku in Super Saiyan 3 maybe. Goku has much stronger attacks than Superman and Superman's strongest enemy might have been about as strong as Frieza, which Goku defeated him as a first form Super Saiyan. Superman might be one to push Goku but not to his very strongest. The fact is that any enemy that has pushed Goku to his limits, Superman would lose to them in an instant. Superman goes full power there might be a little tremor, Goku goes full power and he risks destroying the planet he is on.