I have a rotating list of good burger joints, and South Street is always at the top. Five Guys and Burgers Priest fight for second, but there is something about dressing a burger with non-standard toppings and condiments. For example, you can have the normal green relish, or South Street's own "Gourmet Relish". Go gourmet! Wasabi Mayo? Yup. Maple Infused Onions? Got 'em. Several different quality cheeses? I'm in.
Of course if you are going to make a combo, it doesn't hurt that New York Fries is what they serve. Addictive!