Why Vegeta you may ask. Well I will tell you.
He may not win as many fights or be as strong as damn Kakarot but what I like about him is his determination. His determination to be the strongest pushes him to levels in which he would otherwise not be able to get to. Pure determination makes him and he must be extreamly strong willed to do that. Also, his cockiness can get really annoying to some but I think it is great. It motivates him to get stronger and helps him to remain confident in battles. Oh that's another great thing about him, in battles/fights he never gives up, he fights to the very end and NEVER thinks for a moment that he can't do something.
Also, when there was peace on the earth after the Cell Saga, Vegeta was the only one that kept on with extream training sessions constantly in hundred times gravity. Sure, he was quite reckless in early Dragonball Z. Even in Android Saga, Bulma Capsule crashed with baby Trunks in it and he didn't even bother to see if they were ok. But, I recall in episode 223 i think it was, in the Buu Saga, Vegeta hugged his son and told him he was proud of him. Then soon after that, he sacrificed himself to try kill Buu in an enourmous Explosion and I recall just before he did this, he said something like, "This is for you, Bulma and Trunks." do he did show a side of him which has never been shown before. There is so much more about Vegeta that makes him the greatest but for now that is all. BYE!!