According to an oral history of Friends that appeared in Vanity Fair back in 2012, creators Marta Kauffman and David Crane originally considered Téa Leoni for the role of Rachel, Jane Krakowski for the role of Pheobe and Nicolette Sheridan for Monica. Supposedly Sheridan wasn't Courtney Cox's only competition -- Janeane Garofalo (for whom the part was reportedly created), Jami Gertz, Leah Remini and...Jennifer Aniston were all up for Monica before it went to Cox. And, interestingly, at the same time Aniston was being considered for Monica, Cox was almost cast as Rachel. As for the guys, Eric McCormick almost played Ross and both Jon Cryer and Jon Favreau turned down playing Chandler before Matthew Perry was offered the role.
Before Julie Bowen was cast as Claire Dunphy on Modern Family, Lisa Kudrow was being eyed for the role and Andy Richter was almost cast as her brother, Mitchell. Though we can't picture Kudrow being married to Phil Dunphy (because there'd be way too much spaciness to handle between both Phil and Claire if Kudrow played the part anything like Phoebe Buffay), one would-be casting choice we can actually envision is Craig T. Nelson in the role of put-upon patriarch Jay. To be honest, we've always gotten him and Ed O'Neill mixed up anyway.
Could you imagine Ferris Bueller or Lloyd Dobler as grizzled meth makers? John Cusack and Matthew Broderick were both up for the role of Walter White before it went to Bryan Cranston, which, on second thought, was actually one of those "see it to believe it" casting calls as it is because whoever thought the Dance Dance Revolution-loving dad from Malcolm in the Middle could become so...terrifying?
Before Julia Louis-Dreyfus had one of the most impressively poofy pompadour up-dos the small screen has ever seen, Patricia Heaton, Rosie O'Donnell and Megan Mullally all reportedly auditioned to play the role of Elaine Benes. It's a good thing Louis Dreyfus was cast instead because can you seriously picture Rosie O'Donnell stockpiling female contraceptive sponges and going out with Puddy?
Bridget Fonda revealed in a 1999 interview that David E. Kelley offered her the role of Ally McBeal but that she turned it down to focus on films. Instead it was Calista Flockhart who was destined to have hallucinations of dancing babies and to drink many, many martinis at that boring piano bar.
Buffy the Vampire Slayer
Katie Holmes turned down the role of Buffy to finish high school instead and Sarah Michelle Geller took up the stake instead.
Gillian Anderson was offered the part of Lady Cora but passed, freeing up the role for Elizabeth McGovern. So does that mean that Lady Cora wasn't originally supposed to be American?
The Cosby Show
Whitney Houston almost played Sondra Huxtable on The Cosby Show but turned down the part to focus on her singing career instead (or, according to Cosby himself, lost out to actress Sabrina La Beauf).
Sex and the City
At this point, Sarah Jessica Parker is as molded to the role of Carrie Bradshaw as a pair of arch-destroying Manolos are to your feet but originally it could have been Dana Delany staring wistfully out her window while making five million puns about relationships in a voiceover. Delany, who, at the time, was best known for appearing in Superman, The Larry Sanders Show, China Beach and one of our favorite '90s kid movies, Fly Away Home, supposedly turned down the career-making role because she didn't want to be on a show about sex. And here's another zinger: Sandra Bernhard was offered the role of Miranda but turned it down because she thought the pay was lousy and the original script sucked.
Before Don Draper was played by someone very well-hung, he was almost Hung: Thomas Jane was offered the lead in Mad Men before it eventually went to Jon Hamm. (And, sorry, you'll have to forgive our corny penis joke because, after all, Hamm clocked in at #2 in our list of the Top 15 Celebrity Bulges of 2012.)