The best burgers I've ever had were in NJ. I grew up there but have been living in CA for the past twenty years.
Some of the places I recall having great burgers(remember, this was 20 years ago. Things have probably changed):
What's Your Beef: Rumson
Ichabod's: Sea Bright
Hook Line and Sinker: Rumson
Various small neighborhood taverns around the state, who's names I can't recall, that had a grill behind the bar and the bartender would cook them, or in tiny kitchens off the bar; they always seemed to have the best burgers. 6-8 oz. of beef, preferably on a kaiser roll with simple toppings like sauteed mushrooms and onions, bacon, cheddar cheese sauce, bleu cheese.
So where are NJ's great burgers now? Not the fancy-schmancy stuff like expensive Kobe beef topped with gourmet cheeses and other nonsense that seems to be so common these days. Just your good old fashioned basic burgers with basic toppings.