We have spent time exploring a substantial number of State Parks in Minnesota, Wisconsin, and Michigan in the past few years. Copper Falls State Park is probably our favorite. It may have been the time of year with the cool temperatures and the colorful foliage, but the quality of the campground and trails and the beauty of the area are spectacular. Copper Falls is not on one of the Great Lakes which was the feature we first valued, but it is close enough (e.g., Bayfield) and the other features more than compensate if you need big water.
The following link offers a much larger collection of images. If you are connecting from a computer, you should be able to view the collection as a slide show.