I don't know if I can pick just one favorite hot dog, so instead I'm just gonna wax philosphical about hot dogs at whoever cares enough to read this.

Most importantly is to start with a quality hotdog, something with a natural casing, that snap is critical I like all-beef personally but I'm not outright opposed to some frankenweenies either.

I'm told that in Iceland hot dogs generally contain at least some lamb, that sounds delicious to me, I like lamb. I've actually made and smoked my own hot dogs before so that may be something I experiment with in the future. I actually have a trip planned to Iceland next year so that may be something I try to recreate after I come back (I swear I'm not actually going for the hot dogs, just a happy accident, but I figured I might as well do some recon while I'm there)

A good bun is also important, something well-sized to the dogs, soft but structurally sound that's not going to fall apart and get gross and soggy. When I made my own dogs I decided to go all-in and make my own buns as well. Pretty sure I used whatever recipe was the first Google result was for "sourdough hot dog buns" (because of course the crazy foodie who's making his own hot dogs is also maintaining a sourdough starter) and I was very happy with how they came out. Barring that, get any decent brand of bun, there's not that much variation. I like potato buns, but a regular ol' white bun is fine. I also decided at some point that I like top-split as opposed to side-split buns, but that's more of a nice thing to have than something I'm going to agonize over if I can't find them.

Grill your dogs, or roll them around on a hot pan or griddle, don't boil them. If you're really fancy (even I'm not this nuts) get yourself one of those hot dog roller machines you see at gas stations and sports stadiums, I think those are the perfect hot dogs.

Now onto the real meat of the question - toppings

I don't know that I have any one favorite dog, it all depends on my mood.

I hail from the philly area, so when in doubt when I'm presented with any cheap food item in need of a sauce or condiments, my answer is Cheez Whiz (keep that shit off of my cheesesteak though, that's for tourists, I'm provolone all the way)

Closely-related, you have the chili cheese dog or plain old chili dog. These are all options where you really need to make sure to have a bun that's going to hold up to some heavy, wet toppings. I think mustard is not unwelcome on a chili cheese dog, along with chopped onions and maybe some jalapenos. I'm normally a fan of beans in my chilli, but I don't think they have any place in a chili intended to be a hot dog topping.

I've been to Cincinnati and sampled skyline chili from the source. If you expect chili you're going to be disappointed and confused, but if you go in expecting a spiced meat sauce, you might really enjoy it. I think it makes for a damn good hot dog topping.

Outside of the situations where you're going to have chili available for your hot dogs though

I'm also fan of sauerkraut. For the love of God though, don't rinse and squeeze all of the sauer out of your kraut. Let it be sour and funky. Serve it rwith or without heating it up onto your dogs just as it came out of the can, jar, plastic bag, or crock.

For your typical backyard BBQ where you're grabbing the usual condiments off the shelf to have out on a picnic table for the 4th of July or whatever- ketchup has no place on a hot dog. I'll always go mustard, and often relish (I prefer dill relish over sweet if available) and chopped onions are a welcome addition. I think you'd do well to serve them with some baked beans on the side.

I'd also be remiss if I didn't mention the Texas Tommy, allegedly another Philly-area invention, possibly originating in nearby Pottstown (though that's a big " ^[Citation Needed]^" IMO)

I was recently at IKEA and on the way out the door before a fun night of assembling flat-pack furniture, I grabbed a hot dog with some red cabbage and crispy fried onions, and I also thought that was a great combination (the hot dog itself was nothing special)

For a quick & easy weeknight dinner, I don't think it gets much better than a hot dog or two or three prepared in any of the above styles, accompanied with some boxed Mac & Cheese, and some stewed tomatoes.

For a couple local ish places to me that I've felt like I've always gotten a stand-out hotdog, there's Yoccos in Allentown, Jimmy John's near West Chester PA, and of all places, the gift shop behind the chapel in Valley Forge National Historic Park

And of course, honorable mention goes to Costco for being one of the best deals going.