I live in Chicago! Downtown is really nice and I spent my fair share of time around Millennium Park when I lived about a 10 minute walk away (my dorm was downtown). If you ever get to visit again, I recommend trying some of the neighborhoods. Wicker Park is more hipster/trendy but has a lot of cool shops and Lakeview is beautiful with ALL THE GOOD FOOD. I'm glad you liked it :) The only other major city I've been to in the states is LA, so I'm interested to see NYC/Philly too.