The bun is definitely important and can make or break a burger. No wimpy wonder bread buns please. It has to be large enough to hold every thing together and tough enough to last until the end, not wimp out and fall apart half way through eating. Yet at the same time the bun must be soft so that it breaks down in your mouth with the rest of the burger and your not chewing bun forever.
My favourite topping is my mom's homemade dill pickles, so good. Other sliced dills make a passable substitute most of the time when said favourite is not available.
Another favourite topping are relishes, not that fluorescent green stuff but all others made from such things as tomatoes, onions, dill pickles, hot peppers or, corn. My girlfriend always freaks out about all the relish in the fridge but if your making burgers you got to do it right.
Everything else is pretty much welcome on my burger except maybe only the occasional tomato.
That said the main attraction, the beef patty has to be a substantial hunk of meat. I once ate a burger that had a one pound beef patty- now that was awesome.
