If I were casting the English dub of DBZ Kai...

If limited to FUNi actors:

Goku: Todd Haberkorn
Vegeta: Travis Willingham
Gohan: Colleen Clinkenbeard
Teen Gohan: Vic Mignogna
Piccolo: Troy Baker
Kuririn: Sonny Strait
Freeza: Chris Ayres (Chris Sabat would probably do a good job here too, but why fix what ain't broke?)
Cell: Dameon Clark
Kaio-sama / Narrator: Doc Morgan
Muten Roshi: Bill Jenkins
Fat Buu: Barry Yandell
Yajirobe: Josh Grelle
Yamcha: Kyle Hebert
Oolong: Joel McDonald
Chiaotzu: Leah Clark
Mr. Satan: Chris Rager
Chi-Chi: Brina Palencia
Trunks: Eric Vale
Tenshinhan: Robert McCollum
Bulma: Monica Rial
King Enma: Chris Rager
Recoome: Chris Sabat (minus the mental retardation in the voice)
Kami: Chris Sabat
Android 17: Chuck Huber
Android 18: Collen Clinkenbeard
Gurd / Guldo: Greg Ayres
Zarbon: J. Michael Tatum
Jheese / Jeice: Jason Liebrecht (minus the accent)
Android 16: Jeremy Inman
Raditz: Justin Cook
Dr. Gero: Kent Williams
Ox King: Rob Mungle

If dubbed in LA:

Goku: Yuri Lowenthal
Vegeta: David Lodge
Gohan: Kate Higgins
Teen Gohan: Spike Spencer
Piccolo: Travis Willingham
Kuririn: Brian Donovan
Freeza: Liam O'Brien
Cell: Jamieson Price
Kaio-sama / Narrator: Richard Epcar
Muten Roshi: Steve Kramer
Yajirobe: Robbie Rist
Yamcha: Vic Mignogna
Oolong: Tom Gibis
Chiaotzu: Kari Wahlgren
Mr. Satan: Steve Blum
Chi-Chi: Cindy Robinson
Trunks: Henry Dittman
Tenshinhan: Dave Wittenberg
Bulma: Michelle Ruff
King Enma: Steve Blum
Recoome: Skip Stellrecht
Kami: Michael McConnohie
Android 17: Johnny Yong Bosch
Android 18: Tara Platt
Gurd / Guldo: Derek Stephen Prince
Zarbon: Crispin Freeman
Jheese / Jeice: Michael Lindsay
Android 16: Doug Erholtz
Raditz: Quinton Flynn
Dr. Gero: Bob Johnson
Ox King: J. B. Blanc