1. CRUMB CRUST: Combine crushed vanilla wafers and melted butter or margarine in a medium bowl. Press mixture onto bottom and 1-1/2 inches up side of 9-inch springform pan or 10-inch pie plate. Refrigerate for about 30 minutes or until firm.
2. CHOCOLATE FILLING: Sprinkle gelatin over water in a small saucepan; let stand for 2 minutes. Cook over low heat, stirring constantly, until gelatin is dissolved. Beat cream cheese, sugar and vanilla in large bowl until creamy. Add syrup, gelatin mixture and milk; blend well. Refrigerate, stirring occasionally, until mixture mounds from spoon (about 20 minutes).
3. VANILLA FILLING: Sprinkle gelatin over cold water in a small cup; let stand for 1 minute. Add boiling water; stir until gelatin is completely dissolved; cool slightly. Combine whipping cream, sugar and vanilla in a medium bowl; beat until slightly thickened. Gradually add gelatin mixture and beat until stiff.
4. Spoon half of the chocolate filling into prepared crust and top with half of the vanilla filling. Repeat procedure, ending with spoonfuls of vanilla filling on top. Using knife or metal spatula, gently swirl through dessert. Cover; refrigerate several hours until set. Serve with additional syrup, if desired.