Vegeta.
Akira personally doesn't like him, which may explain so much as to why Vegeta really never got too much of the spotlight as Goku did. Sure, Saiyan Saga Vegeta is an irredeemable prick but by Freiza saga, he actually developed gradually. His complaints of being second to Goku gets tiring at times but it's a vessel he uses to actually keep going on.
It is because of him firing off that energy ki to Cell, is what gave Gohan the advantage he needed to finish Cell off for good since he was struggling even with Goku's help.
I just like the progress of Vegeta's character build. I like that even though he's not prodigy he was lead to believe in surpassing Goku, he's still second-best compared to the rest.