From Wikipedia:
Ethan Coen, film director and screenwriter, who often works with his brother Joel Coen
Ethan Embry, an American actor in Can't Hardly Wait; as a youth credited as Ethan Randall
Ethan Erickson, American actor
Ethan Hawke, a two-time Oscar-nominated Hollywood actor
Ethan Hunt, a character in the Mission: Impossible films played by Tom Cruise
Ethan James, a character from the TV show Power Rangers: Dino Thunder
Ethan Phillips, a playwright, author, and actor on Star Trek: Voyager
Ethan Rayne, a character from the TV series Buffy the Vampire Slayer
Ethan Rom, a character from the TV series Lost (TV series)
Ethan Suplee, an American actor on My Name Is Earl and Clerks II
Also, Ethan and Little Ethan from Passions.
Prince Ethan (comics) of the Heron Dynasty on Avalon, character from the comic book Scion from CrossGen comics
Ethan MacManus, a character in the webcomic Ctrl+Alt+Del