9. Estelle Costanza
Best-known episode: "The Contest"
Actress Estelle Harris' portrayal of George Costanza's shrieking, domineering mother became a regular after she caught him "treating his body like it was an amusement park" in "The Contest." But in addition to the character's ever-watchful eye over her son, it was her love-hate chemistry with Jerry Stiller's Frank Costanza, her contempt for Jerry Seinfeld's snooty parents and superheroic skill for making large amounts of paella that made her truly unforgettable. KORY GROW