9. Buffy The Vampire Slayer (1992)
Now before you say anything, yes, Buffy is a TV series, and yes I know you knew it was on Joss Whedon's CV. For one thing, I've already mentioned it here myself. But what many people don't realise is that it was also a film as well, starring the (still) relatively unknown Kirsty Swanson in the title role, and was in fact released some five years before the series was first broadcast. Back when Whedon was an unknown run of the mill scriptwriter, it was this forward thinking script that first got him noticed. Featuring a fresh take on the horror genre, Buffy Summers was a female lead no longer the victim but tough from the start, and unlike the traditional "Final Girl", didn't need to be borderline androgynous to defeat the villain. Rather impressively, it should be noted that said villain was played by none other than "tears in the rain" himself Rutger Hauer, alongside Donald Sutherland as Buffy's initial watcher. As actors with names that command Hollywood clout (at the time, at least), perhaps they agreed to appear in the film based on Whedon's then groundbreaking script, but join him in the list of people let down by the form that the film would ultimately take. Other than its concept and the TV series (not to mention spin-offs and comics) which it obviously spawned, perhaps the only decent thing it offered audiences was the first big screen appearance of Oscar winner Hilary Swank as a proto-Cordelia. As much as this film could have been improved, luckily the unthinkable Whedon-free reboot (remember how it's not the writers that own their stories) seems to have attracted enough negative reactions on the internet that Hollywood may be wondering if it should go ahead afterall.
Whedon Hallmark: Strong female lead, witty dialogue, pretty much everything that Whedon is famous for, but if you want a more faithful adaptation of his script then check out the Buffy comic The Origin.