For chains - 5 Guys, followed by In & Out. But, Ken, I do have a soft spot for Arby's curly fries. Mickey D's dropped off in my book when they stopped using beef tallow to placate the silly vegans!
We have a local spot that makes THE BEST FRIES that I've ever had. Perfect frites - better than what I had in Belgium! I can't even get close at home, using duck fat!!