This is my personal rendition on a favorite from Quebec. The addition of pumpkin to ordinary mashed potatoes gives them an nice earthiness that goes well with roasted poultry or other autumnal fare. I have not tried it with canned pumpkin but will experiment eventually. Though I don't cook much with butter, you should feel free to add some more to suit your taste.
This one is popular. It has everything and then some. Not something for the calorie conscious! I've used instant potatoes, but of course fresh is best. Good for the holidays.