Heat oven to 350°
Combine graham cracker crumbs, powdered sugar, and melted butter. Press loosely into bottom of springform pan. If you press it in too firmly, it will be difficult to cut into when you serve it.
In large bowl, beat cream cheese, eggs, sugar, and vanilla until smooth. Pour mixture over prepared crust.
Bake at 350° for 50 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.