While I will be up front and tell you that Wisconsin Caches are by far my favorite, I will also mention the the most active area recently almost anywhere is Rockford. They have a group of about 5 or 6 new teams putting caches out down there in some great Forest Preserve areas. Most of them are traditional caches but very well hidden.
Being from Janesville, the Rockford area is almost like caching in my own town. There have been between 10 to 15 new caches down there every couple of weeks for the last few months. Worth the effort and the new cachers are some really great people. I have had the pleasure of meeting a few of them and they scoot across the border our way often.
All of the cache areas are very nice places for all cachers to visit.