Another nod in one episode Vegeta shoots one of Freiza's men and the Wilhelm Scream is used, in Dragonball Z Abridged the scream was used in the same scene right after two of Freiza's henchmen were discussing it.
Hey, It's That Voice!: Those who watch Funimation's One Piece dub will easily recognize Gohan, Piccolo, and Krillin as Luffy, Zoro, and Usopp, respectively. In fact, a lot of the new voices are from the One Piece dub (Freeza=Johnny, Dodoria=Crocodile, Bulma=Tashigi, and so on). Considering both were dubbed by Funimation's in-house voice cast, that's no surprise.
The Other Darrin: Used for quite a few characters whose original voice actors were either dead or unavailable. Several characters were replaced in the dub as well like Gohan and Bulma (the narrator was also replaced), among others.
Also replacing Joji Yanami as Babidi in the Buu arc. (Despite Yanami still being on the show as Kaio and the Narrator.)
Yuko Minaguchi is being replaced by Shino Kakinuma as Videl, due to Minaguchi living abroad now.
Todd Haberkorn, the voice of Allen Walker in D.Gray-Man, took over duties as Android 19, sounding even more robotic than the original dub voice. Similarly, Colleen Clinkenbeard now voices Android 18. Although her original voice actress, Meredith McCoy, was supposedly contacted, Clinkenbeard was brought in anyway as a last minute substitute (since she had filled in for a video game before, and was voicing Gohan anyway).
The broadcast dub also switched Sean Schemmel for Vic Mignogna as the singer for the shortened opening, while the second DVD boxset switched him for Justin Cook.
The Mexican Spanish dub is heavily criticized for not bringing back half the cast, including the voices for Goku, Gohan, Vegeta, and Frieza. This was apparently because of the smaller budget, and the original voice actors asking for more money. However, Laura Torres (the original Spanish voice of Gohan) was brought back to voice Kid Goku in a few flashbacks.
The Mexican Spanish dub has another interesting case: Yajirobe is voiced by the daughter of the original Mexican voice actress, since her mother died in a house accident years ago between the original DBZ and Kai.