9. Buffy The Vampire Slayer
It's easy to forget that Buffy the Vampire Slayer wasn't a purely original IP when the TV show launched in 1997 - it was in fact based on the Joss Whedon-penned 1992 film of the same name.
The movie, starring Kristy Swanson as Buffy, was a mild commercial success but critical failure, with Whedon later claiming that the film was sanitised far from his darker, more sarcastic original vision, prompting him to eventually walk away from the project.
But years later, Whedon was invited to develop the concept into a TV reboot, which he did by partially self-funding a 25-minute pilot episode that successfully went to series.
And like that, with Sarah Michelle Gellar in the lead role, Buffy became a pop-culture phenomenon for its seven-season run.
It's a rare retelling that's better than the source in every single possible way. As such, it's tough to imagine any Buffy fans out there who prefer the 1992 movie to the richer TV series which finally brought Whedon's original vision to life as intended.