I've had so much success with burning bushes in the shade.

How about Hydrangia? "Annabelle' is very nice and it blooms summer to early fall with nice white/cream 12" blooms.

Istanbuljoy

Please, please don't plant Euonymus alata (AKA winged euonymus, winged wahoo, winged spindle tree, BURNING BUSH). It is very invasive almost everywhere.

There are native burning bushes too that are "good guys" (Eastern Wahoo is one).

Native azaleas provide amazing color and variety in shade. You can have a succession of bloom throughout the entire growing season if you choose the right varieties. There are also infinite numbers of hybrids and cultvars.

Here is a link that might be useful: AAS East coast native azaleas

Virginia sweetspire is a good shrub for part shade. There are several cultivars, one is Henry's Garnet. This shrub has lovely white flowers. Another good shade shrub is Mountain Laurel.

Here is a link that might be useful:

I can reccommend also Leatherleaf Viburnum, Pieres Japonica, leuocothoe (rainbow is a nice hybid variety), Acuba, Mahonia Aquaflorim, they have developed some new Camelias which are more cold hardy, you could look into them. If you get a cornus florida (native to america) be sure to get a named variety because they tend to be more resistent to powdery mildow and other diseases. I have several Kousa dogwoods (native to korea I think) 'Milky Way' has done well for me. I have both native and kousa in my yard and I get a prolonged bloom because the kousa blooms just after the natives. You might try planting some bleeding hearts mixed in with Hostas. You can get the spring bloom from the bleeding hearts, which will then go dormant in summer (unless you get a hybrid named 'Luxuriant', which blooms all spring and well into summer) and the Hosta leaves will fill in the bare spot left by the bleeding hearts. The same can be done with blue bells and anemones. Astilbe, lobelia cardinalis, huechera, tirarella, lenten roses, japaneese peonies, are nice plants for shade as well. I love shade gardening because of the foliage combinations which are possible. Keep in mind that I am in the southern edge of Zone 7, you should check the hardiness in your area.