The Michigan State Archives house the government records for the state. The cool stuff is over at Seeking Michigan, a rich collection for history buffs and a pretty good resource for genealogists.
Your best bet is to immediately click the Advanced Search at the top of the page in order to explore the site's many collections. These include:
Also check out the important list of Indexes, including:
Lastly, if you like your historical images in the form of jigsaw puzzles, keychains, coffee mugs and the like, visit the Seeking Michigan giftshop with the clever name, Michiganology.