This is seriously the best pumpkin bread I've ever had. I've tweaked the original recipe quite a bit, so here's my version. I may have posted this before, but it's worth posting again.
3 1/2 C white flour
2 tsp baking soda
1 tsp salt
1 rounded tsp each of nutmeg, cloves, and allspice
2 tsp cinnamon
1 1/2 C white sugar
1 3/4 C brown sugar
Combine all of the dry ingredients.
1 C oil
1 1/2 tsp vanilla (that's my best guess - it's a really generous glob's worth)
2 C pumpkin
2/3 C water
Note: If you are using pumpkin you cooked and blended yourself, which is more watery, use about 2 1/2 C pumpkin and add water to bring it up to 2 2/3 C. I've never tried it with canned pumpkin and I suspect the extra pumpkin I add contributes to the flavor, but I wouldn't blame you for buying a can of pumpkin.
Add 1 bag cinnamon baking chips.
Pour batter into 2-3 greased loaf pans. (I find it bakes more evenly in medium sized pans.)
Bake at 350 degrees for 1 hour, or until toothpick inserted in center comes out clean.
**I don't recommend doubling the batch, because it requires a very large bowl and a lot of muscle power to stir it, and the flour tends to lump, plus I inevitably lose track of how many cups of flour I've added.