I think I'll be in Detroit with my wife in October (2016) for business. We'll stay at the Westin, downtown. She really likes to eat places that are a good deal. Good food, but not to expensive. Frequently places that suit her criteria are hole in the wall type places that don't necessarily show up on review websites. In the past these have included BBQ, Thai, Indian, and Vietnamese restaurants. So no real constraints on type of food.
We will have a car and plan on heading across to Grand Rapids and then up the coast after the business is done, so recommendations along that route are also good. I added Windsor too because the tunnel is just a few blocks from the hotel, so we could definitely go that way before heading west.
I also usually prefer to find a place outside the hotel for breakfast, because there is usually better food for less money (definitely less money, though not always better).