Dogs tend to be extemely personal food - I have been known to gobble a couple of plain ones!
I have definite preferences. I like thinner dogs, not the big jumbo ones. I like each bite to have a good mix of dog and bun. I also prefer the new england style buns, although they're hard to get where I live now.
I'm not too picky about all-beef. I've had good dogs and bad dogs that were all-beef, or a mixture. I've also had things like tofu or turkey hot dogs that were good. Different, but still good.
I would say that 90% of the time I go for a dog with brown mustard. I'd estimate maybe another 7% of the time I have brown mustard and relish. Then the remaining 3 or so percent I have other toppings.
I've never cared for plain dogs, or ketchup on them.
I think steamed hot dogs are the best. They're also good on the grill, with boiled coming in at 3rd place for me.