I just use dark brown sugar on ham. Just enough sweetness and the flavor of the molasses in the sugar comes through. Heat the ham slice on one side until just warm. Flip it over and place the sugar on it until melted and the ham slice is hot. Delicious!
If I am baking a ham, I mix the dark brown sugar with drained crushed pineapple and place it all over the ham. It makes for a nice crust and flavor on the ham. I do poke with a long fork and at the end pour the drained pineapple juice over the ham.