The fourth Ghostbuster. Appeared mid way through the movie Ghostbusters. Also featured in the real Ghostbusters animated series. Most memorable line in the movies.

after being blaster by Gozer because they were present while not being divine...
"Ray, If someone asks you if you are a god, you say YES!"
"tell him about the twinkie"

Winston was played by the actor Ernie Hudson who also featured in the hand that rocks the cradle, congo and most recently (as I type) miss congeniality.