Goten!!

Goten is Goku and Chi Chi's second son.  He is not too bright, but he reaches super-Saiyan level at age 7 with out even putting much effort into it, it just comes natural.  He is one year younger than Trunks and the two of them become best friends.  He fuses with Trunks to become Gotenks.  Saiyan with attitude.  He was conceived in the few days before the Cell Games (go Goku!!) when Goku and Gohan decided to stay at home and train rather than spend their time in the hyperbolic time chamber.  Goten (like Trunks) is SOOOO cute.  He is a great fighter, although he doesn't live for it like his father does.  Chi Chi isn't as protective over Goten as she was over Gohan, and spent a lot of time while Gohan was growing up and studying training Goten like Goku would have (and by all means, she does a pretty good job).  When Goten is young, he looks almost exactly like Goku in Dragonball, and is a great reminder of the original manga, but when he grows up he is a lot less like Goku.  He first meets his dad at the start of the Grand Tournament when he and Trunks entered the Junior division (which they were both angry at because they both wanted to enter the adult division).  He loves to train with his big brother and together they become very strong, although I don't think that he never lives up to his true potential as a Saiyan warrior, but that seems to suit him fine.  Like his father, he tends to be very naive, and trusting, but he is very very sweet.  Although Vegeta is always pushing Trunks to become stronger than Goten (and usually succeeds), the two are the very best of friends and get into a lot of mischief together.