The first meal Jane ever made me was a hamburger with everything. We were 15 and I was sold. 
Since then we have enhanced and improved things to the point where we're pretty sure we have realized
the acme of hamburgers (Peter).

World's Best Hamburgers

Ingredients
(burger meat)
1 lb ground beef
1 lb ground turkey
1 cup rice or bread crumbs
4 or 5 cloves crushed garlic
1/3 cup onions very fine chopped
1 tablespoon tomato sauce
1 tablespoon Worcester sauce
Copious herbs
1 egg
1 teaspoon salt; 1 teaspoon ground pepper
Make sure the meat mix is not too wet - bread crumbs are a good agent to throttle things back if it is.

Accoutrements
Lettuce
Pickled beetroot
Swiss Chard
Fried egg
Pickled Jalapenos
Tomato
Dill pickles
Fried onions
Cheese
Bacon
Bubbies pickles
Grated carrot
The bread is especially important - choose large, artisanal buns (maybe sour dough) which are split and toasted.  Never use chain store "hamburger buns".