HI -- I think some box wood would look nice and this is the best time to buy perrenials.

What horticultural zone are you in?

I'm in central Virginia.

I love little solar power lanterns, maybe in white or silver. That would give some contrast to the dark walkway. Lavender is a beautiful fragrant plant that would be nice sprinkled along the path. Not sure if lavender will grow in your area but a low growing fragrant plant would be inviting.

Good suggestion. Do you have any preferences for edging? The sidewalk is a slate-like concrete stamp so I didn't want to do anything to clash with that (multiple stone types). Any other kinds of rocks, or maybe timbers?

Your walkway appears to be a straight shot to the front door so do employ some asymmetry in your border design. Try not to plant a 'runway' as in the colonial house pic. Your home looks low to the ground, shady and natural. Introduce some 'zig-zag' curves in your border, swoop it around to meet your front foundation plantings and use multiple height plants ranging fr. 12 - 30" ht. such as small evergreens, barberry, azaleas, liriope or other strappy plants that have movement near the walking edges with lights right behind them to diffuse and create alternating light patterns on the walkway, locate lights in a 'zig-zag' pattern, not directly across from one another. Some well placed 'mini-boulders' of local stone would also add a hard vertical element amidst the soft plantings. If this starts to sound too complicated and you need more detailed assistance let me know - I do design online... planbee33@gmail.com

Some light stones around the side walk??

I would create an edge 16 in or so away, fill the gap with white river stone to create the contrast of color and texture. Line it with lights black finished lights at the recommended intervals. Low maintenance, contrast, and minimalist intervention make it beautiful through simplicity.

BPrince300 has some good ideas - but I would like to suggest that you go to the Home Depot and get some landscaping books? They have TONS on walkways!

What about edging right next to the sidewalk with minature mondgrass - does not get leggy, retains its shape and always looks clean! I would definitely start with a low plant like this. You can also look at Gardening Magazines - which sell plant products and some of them even have walkway patterns and designs and will actually sell you everything you need for that look (bluls, plant materials).
I would NOT recommend Azaleas, they get thin and weedy looking over time and must be pruned. Liariope spreds like wildfire and you can NEVER get rid of it all.

I grew up in VA - so what about doing a border run on both sides of some beautiful thick plantings of daffodils and narcissus for spring, along with Va. Blue-bells? Can't go wrong there.
Lavendar likes dry hot weather and does NOT like to have wet fee. Since this a border - try to consider a group of plants that like to be watered all the same? Some lovely Limelight Hydrangeas at the entrance to the house would be nice - they stand straight on sticks, and have a clean modern edge to them mostly because of their new color - I usually plant at least three plants together for a nice full effect.

Evergreens have HUGE rootsystems - so if you ever want to dig them up - a real pain!
nandina is a bamboo - so don't plant this either.

Find out what indegenious plants do well: Black eyed susans - for brigh color and height at the back edge of your borders? Cone flowers (come in ALL colors) - BIRDS and butterflies LOVE these - and they have nice straight stalks?

I would definnitely start with the mini-mondo grasses, and begin to layer in things from edge of the sidewalk out in the grassy area. What about some great colored grasses? These sure do add the look of fullness and also do not need a whole lot of attention and are used in many contemporary landscape plans. the Mono grass (always green) will also help prevent anything from washing onto the sidewalk and when you are done - do NOT forget to MULCH deeply -
I don't know what Black Plastic thingy's you were speaking of BUT anything that has Plastic and Garden in it, CANNOT be good! :-0 Yikes!

I know there are LOTS of wonderful garden centers all around "middle/central Va" - try going to some garden and lawn shows to get some more current concepts on what you can use.

let us know.

Man I love this community :) Thanks for all the advice you guys. I do like the idea of mondo grasses mixed with something colorful. I think small rock edging could work so long as it doesn't look too contrasty with the stamp concrete job. Black eyed susans could definitely work in that space.

Nandina may be called heavenly bamboo but it isn't in the bamboo family.