I have filled in my hosta bed with lenten roses, gumpo azaleas, coral bells, hardy begonia, lamium groundcover. It's nice to have the azaleas and lenten roses in the winter for some shape and color above ground.

Perennials: I use heuchera and bleeding hearts. I also moved in a Jacobs Ladder because I love the foliage combo.
Annuals: coleus, impatience,violas.

Ligularia (!!!), brunnera, rodgersia, kirengoshoma palmata, epimedium, chelone, ferns galore, hardy begonia, hellebore, liriope, mayapples, trillium, arisaema, siberian iris, sweet woodruff, astilbe, aruncus, solomon's seal, astrantia, asiatic lilies in dappled sun, hardy geranium, northern oats sea grass....is that enough to start with? :)

Andrea (shade gardener)

Pulmonaria;
Ajuga reptans "Burgundy Glow",
Impatiens,
hardy geraniums (cranesbills);
toad lilies;
Coleus

-Sprout...(Linda)

No body said Tiarellas! astilbes are my second fav.

columbine
bergenia

wood asters (try "eastern star"), lily of the valley, hakone grass, ribbon grass, sedum (green kinds will grow in shade as long as it's not wet), english ivy, houseplants for the summer, surprisingly purple coneflower and black eyed susans will bloom and return for years in a lot of shade.