I've brewed a couple of pumpkin ales in the past and while it's a personal preference of how much spice aroma/flavor you want in your beer, I've found that doing a "spice tea" at kegging/bottling greatly helps the final product. I've been going with this at packaging time:
o ½ tsp cinnamon
o ¼ tsp ginger
o 1/8 tsp allspice
o 1/8 tsp nutmeg
Just boil them in about a cup of water, cool, and then rack the beer on top of them in the bucket or keg.
Primary: Kettle Berliner Weisse
Drinking: Cut Day Pale Ale, Citra SMaSH, Crystal Ave IIPA, Chocolate Oatmeal Porter