It depends on what type of food you're looking for.
If you want casual and inexpensive I would say you have to go to Lafayette Coney Island. They have been a fixture in Detroit for years. One of the best Coney islands you will ever eat at.
If you are looking for fancy expensive food I might suggest Meriwether's restaurant in Southfield.
But if you don't mind an hour and a half drive then you have to visit Frankenmuth Michigan. It is an old German style tourist town. They have every kind of food but are world known for their chicken. They have a ton of little shops and attractions to visit as well. I believe they still even have a year round haunted house and one of the best house of mirrors anywhere. They also have Bronner's which is the largest Christmas store in the world.
Hope that helps a bit,
Howie "Slobber" Erlich
Deadly Intentions Haunted House