Kuhnhenn's Brewery in Warren is, In my opinion, the best brewer in Michigan. They don't distribute, so they're not as well known as the rest, but their selection beats any other brewery in the state, except maybe Bells or ABC. They also have a ton of wines and meads, a brew store next door, and sometimes even live entertainment.
Check them out online at Kuhnhenn Brewing Co.
, or you can also check them out at the Michigan Beerfest; they usually come to impress. ^_^