"Dawson's Creek"

Paula Cole's hit "I Don't Want to Wait" was not the first choice for the theme song. They originally wanted to use Alanis Morrisette's "Hand in My Pocket," but

PHOTO: The WB

"Family Matters'"

Urkel-mania was no joke. Jaleel White has claimed that once the show shifted focus more to his character, it on the show who suddenly had less screen time. However, Reginald Veljohnson (Carl Winslow) was the only actor on the show to appear in all 215 episodes.

PHOTO: ABC

"Full House"

Mary-Kate and Ashley Olsen landed the role of Michelle because they got through the audition without crying. Except, John Stamos revealed in"" docu-movie that they actually did cry a lot — so John got them replaced while filming the pilot. But when it didn't work out with the other child actors, the Olsens were brought back.

PHOTO: ABC

"Buffy the Vampire Slayer"

were both considered for the role of Buffy before Sarah Michelle Gellar was cast. Even Charisma Carpenter, who ended up playing Cordelia, auditioned. Bonus fact: turned down the opportunity to play Xander.

PHOTO: 20th Century Fox Television

"Friends"

Apparently it was quite the journey to end up with . In the initial pitch for the show, it was called "Insomnia Café." Once NBC became involved, it was changed to "Friends Like Us." Then "Across the Hall." Then "Six of One." The network finally settled on "Friends" shortly before it premiered in September 1994.

PHOTO: NBC

"Beverly Hills 90210"

Luke Perry's character, Dylan McKay, wasn't supposed to be part of the core cast. He revealed to that he was only set to appear in a few episodes but creator Aaron Spelling fought the studio to keep him on. Luke also initially auditioned to play Steve Sanders (which went to Ian Ziering.)

PHOTO: Fox Television

"Ally McBeal"

Ally was originally intended to marry Robert Downey Jr.'s character, Larry Paul, in . But Robert's issues with the law forced writers to cut short his time on the show and the wedding episode ended up being about a high schooler (Josh Groban) suing a girl who dumped him right before prom.

PHOTO: 20th Century Fox Television

"The Fresh Prince of Bel-Air"

Carlton's (Alfonso Ribeiro) famous dance was a running gag on the sitcom and it was based on another popular '90s sitcom star's moves: Courteney Cox's ("Friends") . It was also inspired by Eddie Murphy's "the white man dance" from his "Delirious" comedy special.

"Party of Five'"

Everyone knows this show made household names out of Scott Wolf, Matthew Fox, Neve Campbell, and Jennifer Love Hewitt. It was also the launching pad for a then-unknown . The "Almost Famous" star got her first acting gig in 1996 playing a character named Cory in a season two episode.

PHOTO: 20th Century Fox Television

"Saved By the Bell"

The Bayside High set didn't die with the show. It has been repurposed and used as the school setting for many shows since, "" (which was also called Bayside) and "iCarly."

PHOTO: NBC

"Sister, Sister"

Stars Tia and Tamera Mowry were discovered while attending a "." A producer saw them on set and approached them to develop a show of their own.

PHOTO: ABC

"Mad About You"

There was a big push from Paul Reiser's team for the show to be known as "Reiser" or "The Paul Reiser Show," but network execs weren't into it because the show was about a couple. It was cast member Richard Kind who came up with "Mad About You" in the summer before .

PHOTO: NBC

"Seinfeld"

The concept for the show came while Jerry Seinfeld and Larry David were having a chat about items . They had the realization that their banter was unlike anything they'd seen on TV or in movies and went from there.

PHOTO: NBC

"ER"

The concept for "ER" was originally written by Michael Crichton ("Jurassic Park") as a that Steven Spielberg was going to direct. None of the studios were interested in the project until NBC dusted it off for TV 20 years later.

PHOTO: NBC

"The Nanny"

Some of complained that Charles Shaughnessy's British accent playing Mr. Sheffield wasn't as believable as the one Daniel Davis used to play Niles. But, in fact, Charles was actually born in London while Daniel is from Arkansas.

PHOTO: CBS

"Melrose Place"

The producers decided to pull the plug on the show when it became too unrealistic that the characters would still be living in the . Some characters moved in and out of the building, but Thomas Calabro's character of Dr. Michael Mancini was the only one that lasted the entire series.

"The X-Files"

Gillian Anderson's character, Dana Scully, was (Jodie Foster) in "Silence of the Lambs." Creator Chris Carter even made Dana's to honor the character. Jodie ended up on the show, providing her voice to play a talking tattoo during the fourth season.

PHOTO: 20th Century Fox Television

"Blossom'"

The original pilot for the show had Mayim Bialik's character Blossom as a kid sister side character with the main focus being on . But a female NBC exec suggested to creator Don Reo that he switch it up and focus on the sister instead.