In a large bowl, combine the cracker crumbs, sugar, cookie crumbs and butter. Press onto the bottom and 1 in. up the sides of a greased 9-in. springform pan. Place on a baking sheet.
Bake at 350° for 7-9 minutes or until set. Cool on a wire rack. In a microwave-safe bowl, heat peanut butter on high for 30 seconds or until softened. Spread over crust to within 1 in. of edges.
In a large bowl, beat cream cheese and sugar until smooth. Beat in sour cream and vanilla. Add eggs; beat on low speed just until combined. Pour 1 cup of the filling into a bowl; set aside. Pour remaining filling over peanut butter layer.
In a microwave, heat 1/4 cup fudge topping on high for 30 seconds or until thin; fold into reserved cream cheese mixture. Carefully pour over filling; cut through with a knife to swirl.
Return pan to baking sheet. Bake at 350° for 55-65 minutes or until center is almost set. Cool on a wire rack for 10 minutes. Carefully run a knife around edge of pan to loosen; cool 1 hour longer.
Microwave remaining fudge topping for 30 seconds or until warmed; spread over cheesecake. Garnish with peanut butter cups. Refrigerate overnight. Refrigerate leftovers.