Well, not a chain, but there's a great little drive in joint that's been around forever in SE Wisconson called The Kiltie. Good frozen custard (Wisconsin LOVES custard), had great burgers from a town 8 miles down the road (Robinson's Meats in Stone Bank, not sure where they get their meat now), food tray attaches to the window, and the cutest waitresses! It lost its easy access to the main highway, what...20 years ago?, yet it still keeps going. Good memories there... I'd bet Schnakers has some memories as well
Also, not a fast food place, but you get your food fast...a place called Kuhtz's General Store in my home town. Been there for..75 years under the Kuhtz name. You can get a beer, liverwurst sandwhich, and milking machine udder inserts all in the same place! If someone's cows got out, they'd head down to Kuhtz's to get a crew together. Too snowy to get to work = many snowmobiles and John Deer's at Kuhtz's. One of my wife's best memories is eating graqes with me and my dad during our courtin' days on the joint's steps while watching the small town July 4th parade....
Sigh....I need to get back there again...
Or
If you're talking fast food, well, any place that has a good dollar menu for value. For taste, KFC