My sister and I had a battle with fudge on Christmas Eve that lasted three rounds and ended with great fudge from this recipe (adapted from Better Homes and Gardens "New Cook Book"):
4 cups sugar
2 5-ounce cans (1 3/4 cups total) evaporated milk
1 cup butter
2 cups semi-sweet chocolate chips
7 ounces of a dark or milk chocolate candy bar (cut up)
7 ounces of marshmallow creme
1 cup chopped nuts (optional in my family)
1 teaspoon of vanilla
Line a 13x9 with foil (or we did two 9x9s so we could have nut-ful and nut-free fudge). In a large saucepan over medium-high heat melt butter and then add sugar and milk. Cook and stir till mixture boils and then turn down heat to medium and continue to cook for 10 minutes. Remove pan from heat and then add chocolate chips, chocolate bar, marshmallow creme, and vanilla. If you want your whole batch to have nuts you may also add them at this time. If your family is like our just add the nuts to one of the 9x9s and then pour the fudge on top when it is done. Stir the fudge until everything is combined and continue to stir for one minute more. Spread warm fudge into your pans (or pan) and cut when cool.
The cook book says that you have to store it in the fridge, but we never do this!