Gohan and Videl are by my opinion, the best Dragonballz couple. Why? Well one, they are the most open in their feelings
by always saying dear and honey. Two they seem perfect for each other, and three it was just so cool the way they got together. Y'know girl blackmails guy, guy falls in love, girl falls in love, girl gets eaten by big pink monster, and guy gets so pissed he goes to mystic level. The basic story line for any messed up romance.
Plus Gohan and Videl are my favorite characters. Gohan because he's sweet, kind smart and has an endearing nerd quality to him (I thought he was just considered a nerd by his classmates but after watching him in an episode where he does this painful to watch rap scene as Saiyanman I realize he is a geek. But he's the hottest geek I've ever seen ;)
Videl because she is obstinate in her beliefs, and has the ability to beat up anyone (except the Z warriors) if she truly put's her mind to it, she's the strongest non z soldier human on earth, plus she's smart and nice.
Besides they make more sense than the other couples. Vegeta and Bulma " I know I said I wanted to kill you but it was out of love". Goes either person for that one. Goku and Chichi although Kawaii upon Kawaii, I can't help but remember how they started out. Krillian and 18 well there cool I like them.