I like the shape of your bed a lot. I have a bunch of shady/part shade spots in my yard in Maryland, and have used lots of hostas, heuchera, and tiarella. They all come in such a wide variety of leaf colors and shapes, and you can get hostas in all sizes from teeny tiny to giant.
For a shrub I like Itea or Witch hazel.
Figure out how tall you want your plantings to be, and go to a good local plant nursery and look for perennials in color and texture combinations that are pleasing to your eyes.

Size and shape of bed will be impacted by what you are planting. Most beds need to be about 5 ft deep to allow shrubs and perennials to grow. If you use the Jane magnolia for the left corner, make sure you allow enough room for it to grow. Do a google search and look at the images of that plant, you will see that it is a small tree, maybe 8-10ft wid and the same high.
When I design a bed it is good to see the entire front. So that the left and right are balanced. Also Next to the entry, plant a smaller plant that will not grow as tall at the front door. I dont like big plants crowding the door.
Plant your small tree on the corner, moving if far enough to grow to its mature size.
So from left to right - Jane Magnolia , then maybe 2 or three hydrangae's (depending if their size is about 3x3 ) and next maybe a drawf hinoki cypress Chamaecyparis obtusa Nana ( stays about 3ft high) next to the entry. Some nice perennials are heuchra, and painted fern ( and As Amanda recommended Hostas and Tiarella)
It is always good to start with measurements and some graph paper. Always read and understand the mature size of each plant, then plot out the plants ( at their mature size) on the graph paper. Once plants are placed - make the outline of the bed.

You can always get help with plants at you local garden Center.
Have a great spring

Here is a link that might be useful: More Garden Photos