Preheat oven to 400°. Stir together: Cream Cheese, Cheddar Cheese, Mayo, Ranch Mix, and Garlic Powder. Spoon some of the mixture into each Jalapeno half, wrap with half a strip of Bacon, then secure Bacon with a toothpick. Arrange on a cookie sheet. Bake until Bacon is no longer pink and begins to Brown, about 25 minutes. Remove from the oven and allow to cool slightly. Remove toothpicks and serve.