There's also Grizzly Peak, just a few blocks down Washington from Arbor Brewing Company.
Also in Ann Arbor is Leopold Brothers'. They do all organic brews and have started making spirits in the past few years. Most of their beers are not my cup of tea (er ... my mug of beer), but some folks really enjoy them, and their jukebox is absolutely stellar.
Michigan brewery has good beer at very inexpensive prices. As low as $4 for a 6 pack or $35 for a corny fill.
Hands down the best beer in the area is Dragonmead on 696 service drive just before grosebeck. I think they have close to 60 beers on tap all made on premises. I haven't been there in a few months but may stop to get a keg filled as I am between drinkable homebrews. Keg's at dragonmead run about $65
Have you checked out the michigan beer guide? It's online or at your local brewpub. They have info on every brewery in Michigan.