Heh, I liked both equally when I was a kid. Sometimes I was in a sardines mood, sometimes a Kipper snacks one.
You can eat them any way you like, but I flaked off pieces straight from the can and put them on top of flipsides pretzel crackers with a little bit of mustard mixed with horseradish. That, and a nice Vlasic Kosher Garlic Dill Pickle.
But the smoked kippers are very delicate and would really do well on their own without my decidedly strong condiments, on a cracker, on toast, they would even go well in a dip or on a bagel with cream cheese.