How low is low? And do you want something soft, formal, or...?

If you are talking under 12", any of the spreading Dianthus sp. or Phlox sublata could work. Vinca major, though it prefers more on the shady side, or one of the prostate rosemary varieties. Japanese holly fern

Under 6", Vinca minor or wintergreen (both also prefers more shade), creeping raspberry, candytuft.

Or varying heights are hostas.

Under 18" are the Loropetalum Purple Pixie. You might be sick of them, but it sounds like they would like the spot very well.

Thanks for responding alabamanicole. I saw some photos of yours on the "weeds" thread- beautiful.

Good question on height. I want something ground cover height at the beginning of the planting area- something like phlox would work well- I planted it over my brick wall leading into the back yard and I love the way it creeps and spreads over the wall. Behind that, there is probably room for some plants that don't go above 24".

I'm not sure if I know the difference between formal and informal. The rest of my front yard is pretty informal I guess. This is the only bed.

Thank you so much for the suggestions- I'm going to look the ones I'm unfamiliar with up and see where to go.

Any thoughts on creeping star jasmine or other creepers? I like the look but am afraid of unintentionally planting something invasive.

I believe all of the jasmines, both the confederate and asian versions, will climb bushes and trees, which you definitely don't want here. Anything that creeps along the ground and sets down roots or reproduces by stolons has the potential to be a thug, and most of them are. Vinca is fairly mild mannered but it squeezes out most weeds and takes over right up until the point there's too much sun.

Formal: think "McMansion" subdivision landscaping or the front of an actual McDonalds. Hard edges, geometric shapes; generally the spacing is regular and there are either solid hedges or discrete spaces for each plant.

Informal: More curves and textures. The styles vary greatly but I uploaded a pic of one. If you lean more informal, you could do herbaceous plants instead of shrubs and groundcover --- there are tons of good perennials under 24" available.

Ornamental grasses have deep roots that are perfect for controlling erosion on slopes. There are short varieties (check mail-order nurseries), including blue fescue that blend well in gardens. A taller variety carefully placed can add interest and a focal point. For a sunny spot you might want to check out the new dwarf varieties of Crepe Myrtle. Ajuga makes a pretty low groundcover and comes in several varieties. A little exploring of on-line plant catalogs will give you lots of ideas.

The native azaleas are awesome shrubs.

i would not trust any loropetalum to stay at 18" height but nicole may be able to confirm that from experience. the "smaller" ones they came out with years ago get a lot bigger than originally claimed.
if you would like to layer with increasing height toward the back, sedum could be your front row plants. they are gentle spreaders that remain evergreen (well, this winter did some damage to mine but they seem to be recovering well) and are available in many textures and colors. behind could be 'gumpo' azaleas which remain quite low-growing and come in pink or white. they are evergreen and would appreciate a shaded area since they bloom late in the season.
i really like the look of a ground cover juniper on a slope like yours. look at the many culitvars of juniperus horizonatlis. 'blue rug' seems to have become the standard. not sure about your light conditions as they prefer a lot of sun but i read that they can tolerate some shade but the foliage will not be as full.