Huge Michigan beer fan here. The best breweries are Founders, Bell's, and Short's (which only distributes in Michigan). Breweries that are smaller (and therefore harder to find) but still terrific are Greenbush, Dark Horse, Kuhnhenn, and Jolly Pumpkin. Right Brain and Griffin Claw are both pretty good as well.
If anybody here is reallllly serious about Michigan beer, tickets go on sale for the largest beer festival in Michigan this Thursday morning. It's in Ypsilanti in late July and it's absolutely amazing. I would definitely recommend buying tickets well in advance of the event because it's guaranteed to sell out. http://www.mibeer.com/beer-festivals
Edit: I should also add that Michigan is in the middle of a huge mead kick right now as well. B. Nektar Meadery, Schramm's Meadery, and Kuhnhenn are potentially the three best meaderies in the entire world and they're all in metro Detroit. You all should try some out if you're able to find it in stores.