We have mostly ignored the one-use pumpkin knives this year, but Sur La Table got us with their Pumpkin/Melon Knife. This serrated knife would be good for pumpkins in the fall, watermelons and honeydew in the summer. Now $9.95, on sale for half off at Sur La Table.
You can cut pumpkins without a specialized tool, of course - check out our illustrated tips on how to cut a pumpkin. You can also bake it first to soften.