I'm not big on toppings. I know that there are many who love all kinds of weird (to me) combinations. But far be it from me to tell anyone how to enjoy their hot dog. I've only done this with my son in order to get him to stop using ketchup. It took a lot of tough love, but I think my wife and I cured him of this habit. He doesn't do it anymore to the best of my knowledge, and if he does, he has enough respect for us to do it outside the house.
Seriously, I think the strangest toppings I've seen are corn flakes and cream cheese. Amazing Hot Dog, which has some combinations that I've actually tried and liked (their reuben dog) had a dog that was very popular called my Schmiero. This one had cream cheese. So many people told me that it was surprisingly good. Curiosity got the best of me, so one day at home I put some cream cheeses on a dog I was preparing. I almost threw up! It was almost as bad as when I took a bite of my son's unfinished hot dog years ago forgetting it had ketchup.
It is my opinion that if you don't start with a quality hot dog, it doesn't much matter what you do to it. And if you do have a quality hot dog, you don't need to add anything but a little mustard. I love the taste of a quality natural casing frank. I'll have the other stuff on the side. To me it's like taking a steak from Peter Lugers and drowning it in A1 sauce.