Heat oven to 350°
Combine graham cracker crumbs, powdered sugar, & melted butter. Press loosely into bottom of 10.5" springform pan. If you pack it in too firmly, it will be very difficult to cut into when you serve.
In a large bowl, beat cream cheese, eggs, sugar, and vanilla until smooth. Pour mixture over prepared crust.
Bake at 350° for 60 minutes (until center is set). Place a cookie sheet half full of hot water on the lower rack of oven during baking. It helps minimize cracking, but if it does crack the sour cream + topping will cover it up.
Remove from oven and spread sour cream on top of cheesecake. Return to oven and bake an additional 5 minutes.
Allow to cool and spread desired topping.