I'm doing the paleo thing, so my burger will be on a couple lettuce leaves...which was odd at first, but I've gotten pretty used to wraps and such now. Add some good wasabi cheddar (I'm not a perfect paleo....) and some bbq sauce, smother the thing in cooked mushrooms and onions, and life is pretty much complete.
I seem to recall that cheese was discovered when an ancient traveler carried milk in a gut bag (fairly common for liquids in pre-industrial societies, as the gut has no 'seams' to leak). Wasabi is just ground root - so you could argue it.
As for me - a burger with lettuce (crisp), tomato, onion (chopped or rings, just not the dehydrated stuff), ketchup, mustard, and relish. Hot dog with either ketchup, mustard and relish or chili, cheese, and onion.
And sweet potato fries are the bomb.