Your planting choices might vary depending on the size of the area. Creeping Junipers (Juniperus horizontalis) can be stunning on a bank, but at the same time when it is overused and ill-cared-for it looks like a raggedy mess. If you have a large area, consider a mixed planting that includes Juniper so you've got an evergreen. Another evergreen you should consider is creeping grapeholly (Mahonia repens). It gets the nickname grapeholly from the purple berries in late summer. The foliage is gorgeous glossy green in the summer and dark purplish burgundy in the winter. Meidiland roses are another great choice--they come in white, pink, and red. You could combine the roses with a clump (or three) of lamb's ear (Stachys), offering a beautiful contrast in foliage color and texture.
You might want to dabble with BHG.com's plant finder. From the garden page, click on Plant Encyclopedia and choose Detailed Search. You can specify groundcovers for zone 6 and include other criteria such as height and color.