1. Tien Shinhan
I have been asked many times by friends, 'why do you like Tien so much? Why not Goku or Vegeta?' Well its quite simple, Tien is not over powered. I joke I joke, but seriously I like how Tien never seemed to let himself be ruled out of the manga/anime (excluding that GT nonsense) Tien was also the first bad to become good character in the anime, excluding possibly Launch but that was because of her split personalities. Oh and Oolong, but he wasn't really evil, he was just lonely and liked to abuse his power. Anyway back to the important subject, Tien has some incredible moves and just had a very likable personality. Plus the voice actor was a bad ass and did the voice of Kurama as well!
By Gohan I think I would specify more to kid, teen and future. I became a fan of Gohan mainly because he almost grew up with me, I watched him get older as I did myself. Kid Gohan just had more motivation then anyone at times, plus his anger is just purely awesome. Teen Gohan, even if he technically isn't a teen is a favourite to most, for good reason. He has such a loving and kindhearted personality that was hard not to be a fan of. He was the reason Piccolo became who he is and that is rad on its own. Teen Gohan also had dedication and would do anything to help his friends and family, and I think everyone should respect those characteristics. Future Gohan is the real dark side of Gohan, which I found crazy bad ass. He was more serious, not nearly as light hearted, but he was still a caring friend and mentor to Future Trunks. It showed the never give up attitude of Gohan that I have always been a fan of. He gives it his all even though he knew it wouldn't be enough. And that is why he was a lot better than regular late teen/adult Gohan.
The comic relief of the manga/anime, Krillin has been there since near the start. After his first death I will admit, I was quite depressed, it was a sad scene that is for sure. Then when he came back I went, at least that is over. Until Frieza came along and you know.. BOOM! Which put me back into that sad state, but it didn't last long, since I was awe struck by SSJ Goku and then Krillin came back almost instantly so it got me out of the sadness. Then a few light hearted sagas and movies later, he died again. Then in GT he died again. He didn't seem to like living very much, he seemed to prefer toying with my emotions. But Krillin also created the Destructo Disk which seemed to be more helpful to everyone else than him and he learnt how to impregnate a robot.. So kudos Krillin, kudos.
Son Goku was there since day one, we watched him go from a 11/12 year old all the way to a.. Well 11/12 year old xD But seriously when you are around a character for so long its difficult not to fall for them. Especially when they are basically a super hero, except one with a large amount of crazy transformations.
From the Demon in Dragon Ball to the weird slug creature he turned out to be in Dragon Ball Z. Piccolo was probably the character that evolved the most through the series, going from a heartless killer to sacrificing his life for Gohan and eventually the whole Earth. Piccolo is a hard character not to love.
Bardock may not have been a main character, but after his special and the Episode of Bardock manga I grew very fond of the character. Because he might of started off as a regular ruthless Saiyan however he ended up regretting what he did, trying to redeem himself and sacrificing himself all at once.
Janemba was quite possibly the funnest movie villain of all time, the first form was hilarious with his simple mind and humourous fighting style. While his second form was probably the strongest enemy in Dragon Ball Z if I am not mistaken.
Say what you want about Yajirobe, I would probably agree. But he helped out a lot and he had a sense of humour, so he was a fun character.
I don't care if he was not a proper character, he had a scene in GT.. That counts!