When my wife and I were in Chicago this past summer, we had a really good deep-dish pizza at the Giordano's on Irving Park Road. I suspect the locations are pretty much interchangeable.
It's worth a visit. Just make sure to order fries so you can hear them yell "No fries! Chips!" Can be a bit tricky to find. As somebody else said, it's under the bridge but there are steps there.
Also had good luck at Blue Chicago the couple of times I've been there. Music was great.
For the love of God, do not eat at the Billy Goat. I went once, and could not believe how bad it was. Don't get a drink there either. It's close to your hotel -- if a little hard to find, it's on
Lower Michigan Avenue, like below Michigan Avenue. Look for the stairway in the sidewalk. And then, the actual entrance is on Hubbard -- so, if you want to see it, and check out the pictures on the wall, fine, but do not eat or drink there. I can't stress this enough. And, there's less of a reason to go to any other location. The one on Lower Michigan is the one the guys from the Tribune and Sun Times frequented.
Do walk to Millennium Park if the weather is decent. See the Bean:
http://www.cityofchicago.org/content/***/city/depts/dca/Millennium%20Park/cloudgate800.jpg
You might think it looks dumb. I did at first. But it's awesome. But only from up close. Stand right below it too. Seriously, it's awesome.
If it's cold, the Cultural Center is across the street, and is free:
There's also an Intelligentsia Coffee on Randolph, one block East of Millennium Park, half a block past the Randolph entrance to the Cultural Center.
The Modern Wing to the Art Institute is connected to Millennium Park by a foot bridge. If your down there at lunch time, there's a good, if a little expensive restaurant in the Modern Wing, and you can go to it without paying to get into the Museum (which is worth a visit if you have time, and are into that kind of thing).
Deep dish pizza can be good, but I always regret it the next day. If you do eat it, and you think you might want one more slice, don't do it. Stop eating. You'll be glad you did.
Giordano's and Lou Malnati's are about equal to me. Both have multiple locations. I've never been to Gino's East, so I can't speak for it. People do swear by Pequod's, but I haven't been there either. There's also Pizzeria Uno and Pizzeria Due.
Worth noting, you'll wait about 45 minutes for your pizza to be baked once you order it.
Pizzeria Uno/Due have you order while you're still in line and waiting for a table.
For Blues, I haven't been to Blue Chicago. I've done Kingston Mines which is good. B.L.U.E.S. is right across the street from it. And there's also Buddy Guy's.