Are you looking for super high-end or more casual? Along the lines of the very best (and these are some of the best restos in the country) there is Alinea, Charlie Trotter's, L2O, Tru, Blackbird, SPiaggia, and Les Nomades, Schwa. Out of those, Alinea is the best, if you're into the kind of food some people call molecular gastronomy. Charlie Trotter has been around forever, is still doing his thing, and some people say the restaurant is better now than it has ever been in its 20 year history. L2O is Laurent Gras' seafood-focused restaurant. It is very good, and I would recommend it to anyone, although I've been there twice and one meal was incredible and the other left a lot to be desired. Still, if you love seafood (and Chicago is not a good seafood town in general, Gras' brigade shows a mastery of technique and some really interesting thought behind their food. Tru is another Chicago standby. Been there forever, always been good. Blackbird is Paul Kahan's flagship resto and there really isn't much else that needs to be said. Spiaggia is one of the most popular fine-dining spots in the city, for a good reason. Les Nomades is a relatively unknown French resto in the city. It doesn't get a ton of press, but it is an absolutely incredible meal and if you have the money, it is worth it. Schwa's meal is sublime, there is no other way to say it. Before I left Chicago to come to CA, Schwa was by far the best meal of my life. I loved every single fucking dime I spent there, but reservations are impossible to get, so it might be too late for that. Going down the line in terms of cost, next there is Riccardo Trattoria, Avec, Cafe Iberico, mk, and Green Zebra. Riccardo Trattoria is simply the best Italian in the city. In the same neighborhood as Alinea, but got only one point less than Alinea did in the Zagat guide. A great meal, for sure. Avec is Paul Kahan's second Chicago restaurant and is really good too. Communal seating and small/large plate format. You will be happy. However, no reservations are taken, so if you really want to make sure you get a seat without waiting, get there within an hour of the beginning of service. Cafe Iberico, I've never been there, but have heard nothing but good things. mk is a restaurant I used to stage at, and although it's nothing out of this world, the food is executed well and the prices are not too high. The highlight at mk is its desserts. Pastry Chef Tony Galzin is simply a genius and it would be prudent to try and hit mk for dessert whether you eat somewhere else or not. Green Zebra is a vegetarian restaurant that will absolutely blow your mind regarding vegetarian food. I have been 3 times, and some others here have as well. You will not realize you're eating a vegetarian meal. Every single bite is so singularly satisfying. I love this restaurant, and prices hover around 10-18 a course. Going even lower, into terms of almost downright cheap places, is the Grocery Bistro, the Bristol, and the Paramount Room. They are all basically the same. Restaurant/Bars that are doing very unassuming food and doing it nearly perfectly. Typical American/French bistro fare. Burgers, salads, some braises, simple food done incredibly well. They all have websites with menus. You can get into any of them at any time most likely. And don't forget that Chicago has great dirt cheap food. Whether it's getting a dog from Byron's, a gyros from Mr. Beef, or just getting some cheap Mexican food, it is dirt cheap and very satisfying. If I could only recommend one from each group it would be this: Super high end- Alinea Moderate- Riccardo Trattoria Lower- The Bristol Lower than Low- Mr. Beef or Steve's.