18. Sidra Holland
Best-known episode: 'The Implant"
Oh, they're real — and they're spectacular. In the glorious pantheon of one-shot "Jerry's girlfriend" characters, none makes an impression quite like Teri Hatcher's Sidra, the woman Elaine accuses of having fake breasts. ("This chick's playing with Confederate money!") Sidra reappears in the courtroom finale as the arm candy of lawyer Jackie Chiles, who confirms that they are real and spectacular. At the time, Hatcher was a 29-year-old starlet best known for low-budget flicks like Brainsmasher: A Love Story. But she went on to fame and fortune — the only actress who can claim to be both a Bond girl and a Seinfeld girl. ROB SHEFFIELD