There are people that will ONLY use ketchup on a hot dog, those that say it HAS to be mustard. For the record I like both, together or apart. In fact, you want to try something I love, it's sriracha!
But the new hot topping for hot dogs is peanut butter! Smooth or crunchy, you might see it at a hot dog stand in the near future. But it's apparently tasty, at least according to the folks at Food&Wine.
Read more here (pops).