Preheat the oven to 350°F. Grease a 9-inch springform pan and set a pan of hot water on the bottom rack.
Mix the graham cracker crumbs, melted butter, and sugar. Press over the bottom and about two-thirds up the sides of the pan.
Bake the crust 5 minutes. Let it cool while you make the filling.
Beat the cream cheese, sugar, and vanilla until smooth and fluffy, scraping the bowl.
Add the pumpkin, eggs, cinnamon, and nutmeg and mix just until combined. Don't over-mix.
Pour the filling into the crust. Bake on the rack above the water pan for 60 to 70 minutes, until the edges are set and the center still jiggles slightly.
Cool to room temperature with the ring on.
Refrigerate at least 4 hours, or overnight (up to 24 hours).
Run a thin knife around the edge, release the ring, and top with whipped cream and pecans.