Spaw referred to the documentary Hamburger America in his post above. I am fortunate to live here in Connecticut where 2 of the 7 establishments featured are located. One is Louie's Lunch (New Haven) - purportedly the place where the hamburger was invented...these are cooked vertically,, served on toast, and if you ask for ketchup (or catsup) you are asked to leave. The other is Ted's World Famous (Meriden) where they steam equal amounts of hamburger and cheddar cheese and serve it up on a fresh roll. Ted's should taste awful, but just the thought of this delectable meal tempts everytime I go within 10 miles of the place (twice a day) - Roadfood.com rates Ted's at 100 miles - meaning you should be willing to drive 100 miles out of your way to get one.

dw