just a couple things to add...
Cafe Spiaggia is one of my favorite restaurants in Chicago. It is located right at the corner of Oak and Michigan, and if you didn't know it was there, you probably wouldn't notice. It is great italian food, and well known. Spiaggia is also in that building, but it is more expensive and I've heard not worth it. I always stick with the cafe. My favorite thing there is the gnocchi with wild boar ragu.
Also, my husband and I go every weekend for lunch at Bistrot Zinc, which is on State near Division. The first time we went there we were totally hooked because it made us feel like we were in Paris. Everything I have had there is great, and it's also close to the shopping in the Mich Ave/Oak St area (as is Gibson's, a famous steakhouse mentioned earlier, and Tavern on Rush--these three are all within sight of one another).
If you are looking for something a little more off the beaten path (I love Saks, Neimans, Barney's, etc, etc, but sometimes you want something more local), try shopping on Damen. My favorite lingerie store is called G Boutique, on Damen right near the 90/94, and there are some cute clothing boutiques right on that block as well as a popular sushi place called Coast. There are also some really cute home and clothing stores on Division right around Damen. Finally, there are cute boutiques on Armitage just west of Halsted (including Active Endeavors). This is the Lincoln Park area.
Finally, I just made it to the aquarium this weekend, and it is pretty amazing. I stayed for 3.5 hours until they kicked me out because they were closing. They have a baby whale right now.
