Goku's a good role model. He fights evil, is pure of heart, loves everyone, forgives his enemies, and always does the right thing. He's totally righteous. As cool as that may be, it is not realistic, and I've never fully identified with Goku as much as some other characters because of how distant his personality is from real-life.
As a kid, Cell was my favorite character. He was evil, cool-looking, and could steal people's power. His potential was infinite, and all of it relied simply on a unique ability. To a young boy, the idea of inifinite power and world domination is pretty sweet. But I grew out of my overrated taste for Cell, and looked towards another character: Vegeta.
Vegeta is one of the most dynamic characters in the show, and deals with some of the most tremendous internal struggle. His father, king of the Saiyans, was killed by Frieza. All of his people were exterminated. He, the prince of his people, was enslaved by Frieza and his planet cartel, and forced to train hardcore every day just to do Frieza's evil bidding and destroy innocent people in the name of money that he will never see. You can imagine the shame of being a prince of an entire planet and being treated like a work horse. He despised Frieza. He hated him more than anyone, until a new challenge arose - Goku. Unaware that there were any other Saiyans left in existence besides Raditz and Nappa, Vegeta initially considered Goku to be just another little bug.
Goku was more than a bug. He was a goody goody who barely trained but gained enormous power, while Vegeta trained to the brink of death for the smallest gains. Together, they destroyed Frieza, the bane of Vegeta's existence, but it didn't end there. The Saiyan prince had a new nemesis. Vegeta trained so hard, only to be out-shined by a lazy, sleepy vagrant of his own kind. Vegeta, the prince of Saiyans, was destined to be the Super Saiyan, but Goku beat him to it. He beat him to the next level of Super Saiyanhood every time. You can imagine how much Vegeta struggled inside.
Vegeta's determination, hatred, and jealousy is what makes him the best. He's the closest character to what we would feel if we were in his shoes. He is strong, both physically and mentally. Goku never had to work hard for his shit. He's just gifted at everything. It's like he's on steroids and Vegeta's trying to compete with him natty. It's a lot of shit to take in, but Vegeta never gives up. He keeps training to surpass his nemesis. He is the Saiyan prince; the prince of Vegeta; the heir to an entire planet and race. All he wanted in life was to be accepted for who he was supposed to be.
The creator of DBZ himself said that he didn't really like Vegeta, and that he only kept him around because the fans liked him. I think that if this wasn't the case, we would have probably seen a lot more content involving Vegeta.
We can all learn from Vegeta. His thirst for vengeance and appraisal as the true Saiyan prince is enough to fuel us all to become the strongest we can be.