I would imagine Millenium Park will be high on most lists from this point forward. I think Weiner's Circle and Bill Goat could quite easily be skipped - both fun, but I wouldn't book an internet fare with those two places as destinations. You can get a good hot dog and a mediocre cheeseburger in many places - Chicago style pizza and Italian beef, now that's worth the trip! You're not going to find them anywhere else, at least edible versions.

Things I would add to the list, in addition to Millenium Park: a drive along Lake Shore Drive from Hollywood to McCormick Place (including a drive to the Planetarium to see the skyline from that vantage point), a walk along the Magnificent Mile (N. Michigan Avenue), the magnificent Marshall Field's on State Street (to shop) and Carson, Pirie, Scott (for the architecture), a ride around the Loop on the "L," and the carmel corn/cheese corn mix at Garrett's Popcorn shops.