Assuming this ever happens (and I have my doubts that it will) here are my choices for new Ghostbusters...
Charlie Day:
He'd be Oscar, the main character. A perpetual slacker and loser, he is forced to join by his mother and Peter so he has a job.
Dule Hill:
and
Josh Radnor:
These two would be the serious Ghostbusters. They'd be actual doctors like Ray and Egon. Both are great straight men for Day to play off of, and Josh Randor is hillarious on How I Met Your Mother when he goes into pretentious, dorky, ass hole Ted persona.
Finally, in the role of the female Ghostbuster
Mila Kunis:
She is hot and is great in comedies so why not?

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