Hi -- You're going to have a great time. You are getting super advice here. I would suggest going to the observatory in the John Hancock Building instead of the Sears Tower. The line is usually shorter, and the view is wonderful! Definitely a cool big-city experience.

I'm glad you plan to ride the subway. It's easy and fun.

Also, one dining suggestion: go to Foodlife in Water Tower Place. It's got choices for everyone in a very nice "food court" area, and then you just pay for it all as you exit. The food is definitely better than typical food court fare.