I don't have particularly high hopes about Ghostbusters 3. I don't think anything will actually come to fruition. The movie has been "officially" on and off for years. The closest thing to there ever being Ghosbuster 3 is the video game that was released on nearly every console a few years back. Despite a few gameplay flaws, the game was a great tribute to the films. Minus Rick Moranis and Siguorney Weaver, pretty much every major character was voiced by the actor who portrayed them in the films. Bill Murray, Dan Akroyd, Harold Ramis and Ernie Hudson are all accounted for and in a nice touch the game developers managed to get a few additional actors to reprise minor roles like Jeanine, Walter Peck the EPA guy and even the guy who did the voice work for Vigo the Carpathian. Honestly, I'm not sure if a third movie could live up to what they did with the game really.