Hosta / variegated Hosta

If you want evergreen/winter interest, I'd consider including a small spreading yew, like Taxus cuspidata 'Dwarf Bright Gold' or 'Nana Aurescens'. Yews are perhaps the most shade tolerant of any conifer/needled evergreen and the bright gold new growth coloration of these two will brighten up a very shady corner. Yews are also some of the most tolerant conifers to pruning as well, so easy to trim if they get too large fr that spot, although that is doubtful with either of these cultivars. And very winter hardy as well.

You can accompany the yew with some hostas (especially those with gold or cream variegation), the gold leafed bleeding heart and/or some ferns.

1) I think you need some matching mounding shapes on the opposite corner by that cone shaped conifer. 2) I have had plain old-fashioned annabelle hydrangeas growing in such a space. Michael Dirr, the shrub guru, claims he's seen them growing in very dark dry shade, so I tried it in a bad spot. Their form was open-ish rather than dense and full, flowers were sparse, but they were cheap and green & filled up the hole very nicely with a different texture. They add a bit of loose height to a naturalistic grouping of hosta, ferns, variegated Solomon's Seal, a carex for linear shape, all over a base of plain green sedum. The carex and sedum stay green all winter for me, with the hydrangea flower heads persisting above. My planting is very informal...a sheared yew and one of the larger hosta, or a mass of a medium-sized one, would give a more tailored look if that is your preference. Pachysandra or epimedium would also offer a tailored evergreen groundcover, even if originally in just a single patch in your white gravel while you wait for them to grow enough to spread further. Oh, and you could put a bright vase shaped hosta in your urn beside your door, if you want to repeat that shape and integrate the urn. But do trouble to shop a proper nursery to choose from the 100's of varieties of hosta. The hosta board here would be able to suggest a vendor in your area who has a display garden, and there are excellent online hosta specialists who mail order very fine plants, but I strongly recommend against buying hosta from the big boxes, though I think they're fine for simplest hydrangeas or ordinary yews. Hosta have some disease issues being spread by cheapo irreputable vendors, and you want strong plants that haven't been prematurely forced into weak growth.

Wow, thank you all for your fantastic suggestions! I am beyond appreciative. I have some great ideas now. Can't wait to get started. Maybe it would be best to start another post, but now I'm sort of wondering if I should match it on the other side of the window, like samarnn said. I got a good deal on some ivory halo dogwood (which looks like it will do full shade - I'll try it and if it has trouble, I'll move it to the backyard). Should I plant one of those on either side of the window and mix some hostas, yew, hydrangeas, etc. in to try to match on both sides?