My perfect burger is a nice fresh beef patty between a toasted bun, dripping with cheese, ketchup and mustard. If there's a pickle on board, I'll pluck it off and eat that first. Sometimes grilled onions are okay (never raw) and hardly ever will I eat lettuce, tomatoes or mayonnaise. I prefer good old fashioned, greasy ground beef as opposed to chuck or round. It's gotta be juicy!!
While history can't say with certainty when the first hamburger was created, we do know it was long ago. This site will give you an interesting history of ground meat and burgers. And if you'd like to make your own special hamburger this site claims to be THE place for hamburger recipes. The one I found most interesting is the bacon and banana burger. I don't think so! But as of late, and without a doubt, the most expensive burger sells for $5,000 in Las Vegas' Fleur de Lys at Mandalay Bay. The burger, (a kobe burger stuffed with foie gras and black truffle, served on a brioche truffle bun and garnished with Chef Keller's special sauce) is so good that it comes with a free bottle of 13 year old wine (Chateau Petrus 1995...the real reason for the price tag).
Back down here on earth, I recently visited Red Robin (touted as America's Gourmet Burgers and Spirits). I had the 5-alarm burger. It was good (I like spicy), but it just didn't hit the spot. I regret that I didn't try something super cheesy.