I like to use those Hebrew Nationals whenever I make hot dogs. I'll cut bacon up into small bits until they're crunchy then remove them from their fat and add some freshly minced onion into the fat until they're transparent, then I'll throw my dogs onto it and roll em' around until the onions are fully caramelized. I'll pretty much eat that on a bun with the bacon bits, onions and a mixture of mustard with Louisiana style hot sauce.
If I really had the time to make a hot dog I'd consider to be optimal, I would make elongated french rolls(with the thick, shiny, and crunchy exteriors) that were big enough to fit just a bit more than an entire hot dog. I'd cook the hot dog in the same way but I'd slice the onions long-ways, I'd cut the tips off the rolls then reach into them and either pull all the doughy bits out or just force them to the sides of the interior as best as I could to make room for the dog, then I'd rub my mustard and other condiments along the sides of the interior, put the hot dog inside, then stuff it with the onions. Most hot dog buns are just too bland or light to really add anything to the hot dog that I'd really like.