Nearly all of Joss Whedon's major projects are available for instant viewing on Netflix, as well as other common sources of streaming video, like Hulu Plus and Amazon Prime. As of January 2014, the movies and TV shows below are available to stream instantly on Netflix in the United States.
While watching this entire list would be impossible to do in a day, a week or even a month, they're all must-see movies and TV shows for fans of Joss Whedon. Anyone who hasn't seen works by Whedon can find something to love among these streaming titles. "Buffy the Vampire Slayer" is always a good place to start, since it is what brought Whedon to the attention of TV fans and critics alike.
In addition to the items on this list, Netflix is also streaming the meta-horror film "The Cabin in the Woods," which Joss Whedon wrote but did not direct. It features some Whedonverse actors, including Fran Kranz ("Dollhouse"), Amy Acker ("Angel"), and Tom Lenk ("Buffy").