I like his personality.(I'm not counting GT as canon okay?) He's just really....normal. Lol. When compared to the rest of them. XD
Also, much to my sister's dismay, I like his hair. Yes. I know it's a bowl cut, and in real life would look like pants, but in the show I like it. ^_^
I'd have to say his personality as well. The horrors that he's lived with in the future really made him into a character you have to like. Unlike some characters he knows how bad things can get and so he doesn't have sympathy for characters like Freeza or Cell. If he gets a chance he will unleash hell on them. He might have been a bit naive about powering up, but he never really had that kind of training freedom and certainly Vegeta didn't give him pointers.
A good guy with a strong sense of what the right thing to do is.