Trying to make as complete a practical list as I can. This is as comprehensive as I got. This is assuming that in the imaginary show or movie the characters wouldn't be kids anymore. If you have better ideas, or more characters,??please share em.
Aang-Elijah Wood (Frodo Baggins, LOTR)
Azula-Kelly Hu (DeathStrike, X-men 2)
Bumi-Jim Carrey (Grinch, Grinch Stole Christmas)
Earth King-Ben Affleck(Rafe, Pearl Harbor)
Guru-Johnny Depp(Jack Sparrow, Pirates)
Iroh-Gean Hackman(sub-commander, Crimson Tide)
Jeong Jeong-Gary Oldman(Main Terrorist, Air Force One)??
Jet-Hayden Christensen(Anakin, StarWars)
Katara-Jennifer Connely(Hulk's girlfriend, The Hulk)
Long Feng-Jet Li("Ox" , Fearless)
Long Shot-Ben Stiller(main guy, Night @ Museum)
Mai-Angelina Jolie(wife in Mr.&Mrs. Smith)
Ozai-Hugh Jackman(Wolverine, X-men)
Pakku-Harrison Ford(take your pick)
Roku-Ian McKellan(Gandalf, LOTR)
Smellerbee-Renee Zellwinger(wife, Cinderella Man)
Sokka-Orlando Bloom(Will Turner, Pirates)
Suki-Keira Knightley(convenient isn't it?) (Elizabeth, Pirates)
Toph-Jessica Alba(Susan Storm, Fantastic 4)
TyLee-Jennifer Gardner(Elektra, Elektra)
Ursa-Kate Beckinsale(main lady, Pearl Harbor)
Yue-Bryce Dallas Howard(blind girl from The Village)
Zhao-Jason Isaacs(Tavington, The Patriot)
Zuko-Juaquin Pheonix(emporer, Gladiator)
