In food processor, place ginger snaps and turn into crumbs. Add butter, and 1/2 cup sugar. Pulse until it all looks like sand. Press into bottom of a spring form pan. Bake at 350 for 5 minutes and cool completely.
In large mixing bowl, add cream cheese, whip until creamy, make sure to scrape down the sides of the bowl occasionally. Add milk, pumpkin, sugar and spices. Mix well, scrape sides of bowl. Add eggs, 1 at a time. Combine well, scrape sides of bowl.
Pour mixture into the cooled pan and crust. Bake at 325 for 1 hour and 15 minutes. Cool for at least 1 hour, and then chill.