Dawn, the pic in my siggy shows azaleas and rhododendrons. BTW, it's NOT my yard, unfortunately!
It's difficult for me to say what would be most suited to your garden, as there are distinct variations in shade, therefore a wide range in the types of plants that can be successfully grown. Having said that, I'm going to give you some links to browse, and hopefully you'll find plants that you like, that would work in your garden.
First, a link to the
~American Rhododendron Society~ , specifically the Proven Performers page. Scroll down and find the azaleas/rhodos most suitable for Michigan. The entire site is full of great info!
As far as some of the perennials I mentioned are concerned, the
~Monrovia - Shade Garden Collection~ lists many of them (with pics, light requirements, etc.), in their Collection Plant List. The pics and info are great!
I mentioned hostas (and you'll see some on the Monrovia site), because they're so easy to grow, with a vast range of varieties (approx. 10,000!), from cute mini ones, to very large specimen plants. Some hostas prefer more sun than others, and if you are interested in purchasing them, make sure you choose a slug-resistant variety.
I hope this helps!
Kim
* I'm having some trouble with the Monrovia link. I'll see if I can fix it!