I love Mchenry County. But I must tell you, Bull Valley has a reputation for being "haunted"
This is just me...but I have always that that Greenwood, IL in McHenry County (by Galt Airport) is the most adorable little town and would love to live there someday if I had kids. They seem like a tight knit community too, and have fun with the little airport being there. I dont know a thing about taxes....but its close to bull valley and not in crystal lake (more expensive I presume)
its also near glacier park, another one of my favorite places to do some walking/hiking.