Combine crumbs, sugar and margarine; press onto bottom of 9-inch springform pan.

Combine cream cheese and sugar mixing at medium speed on electric mixer until well blended. Add eggs, one at a time, mixing well after each addition. Blend in chocolate pieces and vanilla; pour over crust.
Bake at 450, 10 minutes. Reduce oven temperature to 250; continue baking 35 minutes. Loosen cake from rim of pan; cool before removing rim of pan. Chill