I have lived in Illinois most of my life and it's getting bad to live here, but I will say there is plenty to do.
For one, chicago has many places to visit, the shedd aquarium, the planetarium, the field museum, museum of science and industry, art museum, around the july 4th weekend there's the taste of chicago. I would suggest not driving in the city, there's not many places to park unliess it's a big place. For the taste I take the train in from elgin and walk to grant park from union station.
If you like camping/hiking, there are numerous campgrounds. The state parks, the army corp of engineers parks and the local county ones. One of my favorites is starved rock state park. Another is lithia springs in lake shelbyville which is an army corp park.
It all depends on what you want to do. A visit to Springfield is a must. Galena, Il. as stated by someone else is nice.
Every state has good places to visit, you just need to have an open mind and not write if off because it's not a good place to live.