Oh excellent choices, Montalban as Khan was so perfect. I would like to add a few more to your wonderful list here.

Michael J. Fox as Marty McFly
Christopher Llyod as Emment Brown

Quote Originally Posted by Lady's Human
Ricardo Montalban as Khan

Harrison Ford as Han Solo

ALan Alda as Hawkeye Pierce

George C. Scott as Patton (He was better as Patton than Patton was as himself, in reality George sounded like a whiny kid)

Donald Sutherland in "Kelly's Heroes" (Okay, the entire cast of Kelly's Heroes, but the best line in the movie is "Always with the negative vibes, Moriarty, always with the negative vibes!")

John Wayne as Donovan in "The Fighting Seebees"

John Belushi and Dan Akroyd in "The Blues Brothers"