looking more closely at the article, it looks like a feature for the new food network magazine. i'll try and flip through an issue today and see if it's in there, and give you a heads up.
I like how you went to one of the nicest restaurants in Charleston and got a burger.
Seriously though, Poe's on Sullivan's Island, SC has an amazing burger. I'm sure it's better than whatever the hell that place in Spartanburg has to offer.
I'll vouch for Rotier's in Tennessee, Nashville to be exact. A cheeseburger, fries, and chocolate shake are always high on the agenda when I go back to visit (well, it's usually a toss-up between that and Arnold's for meat-and-three). 'Tis a perfect, simple burger.
One fast food burger I'm curious about is Steak N Shake. I know that they probably will not compare with any of the places in this thread (I've been to a few including Father's Office & Joe's), but judging them against In N Out would be appropriate.
As far as fast food burgers go, I enjoy the Farmer's Burger from Farmer Boys a great deal....
Not much from the GAFachusetts crowd in here. I've heard of the place they listed, but I've never been there before.
My own suggestion is kind of a weird one: The Burger Dog at Petit Robert Bistro is Boston. It is a burger served on a french baguette. It is really simple, but amazingly delicious.
In N Out is better I think. Not leaps and bounds or anything, but definately better. However, Steak N Shake has by far the best fast food milkshakes you can get.
EDIT: Well, Culver's makes really good milkshakes too. I'm torn on that now that I think about it.