Not sure where you're located, but a gravel driveway may help to soften the house versus asphalt or concrete. Soften up the area with grasses. Here's a link to a photo of grasses with a hot color palette http://www.spacemakerpress.com/catalogue/catimages/st05imgb.jpg You can always choose a more muted color palette as well. I would definitely tier the plan heights so they're taller against the house and gradually get lower. It would help to bring the house to human scale and not appear towering above. The pathway could be in a natural stone - the same color as the gravel driveway (if you can do gravel).

You have done a beautiful job of tucking plants into the crevices of your retaining walls. Your house trim color is perfect -- just slightly lighter in hue than the retaining wall blocks. First I would paint the big, flat gray wall slightly lighter than the blocks and slightly darker than the house trim. The concrete walk and stairs I would stain a mottled blend of the blocks and the house trim colors. Next would be to paint the railing black or the house body color. Now, think of the following as creating a light, airy trellise structure from the walk-level face of the (currently gray) wall to about 7' above the top of the wall (using 6x6" posts attached to the wall) with a corresponding line of posts sunk into the terrace level 2' in from the outside edge of the wall-attached posts. The inside posts would be about 6-8" higher than the outside posts. Put 4x4" wood to attach the outside line of posts to each other and do the same with the inside line of posts. Run wood pieces at the top of the two lines of posts from the inside line to the outside line at about a 45 degree angle. They would be cantilevered up at the terrace level. Across the top of the angled pieces create your top trellise boards which run parallel to the two lines of posts. OK. There you have your basic structure. You might want to extend the structure around to follow the street side of the terrace. You could then follow the suggestion of reom10 above about creating a bench-planter on the terrace side. Your spacing of the boards parallel to the gray wall and attached to the outside posts would determine how private you wanted your terrace to be. You might want to soften the terrace "floor" by using something irregular like flagstone with groundcover plantings between the stones. From the latticework on top of your structure you could hang seasonal flower baskets. Plant vines to go up the trellis and spill down the wall. How about planting a row of tall, narrow shrubs along the neighbor's fence above your terrace to help add to your privacy and make your yard feel less 'structured'? Or, how about patio table/s with umbrellas to block your neighbor's view? Anyway, you have a fun project ahead of you.

What climate zone are you in or where are you located? Can you take a photo that shows the entire front yard? I can't tell where you park or how guests walk to your front door. If you search Houzz for 'entrance gardens' you will see many examples of homes with wide paths leading from the street to the front door. Do you like to garden? You have a lovely house and would not want to hide any of the porch area so keep the plantings around the porch low. You can plant some taller plants at the base of each post but these should also stay low and not get higher than 3' to 4'. It looks like the garage may be in the back of the house with a fence along the driveway. You could have low growing roses along the fence and flower beds at the front of the house if you like to garden. Location and more pictures would help us to give suggestions for the garden.

Sorry I am so late coming to your site - you are an inspiration to all, homeowners and advisers alike. For your planting advice, I suggest you call Merrifield Garden Center to see if they will come out your way. They currently have wonderful garden centers in Merrifield and Fairfax (both in Fairfax County) and a new one in Gainesville, but they may come further south to wherever you reside. (www.MerrifieldGardenCenter.com) Even if they don't send designers to your area, they are worth a trip to see their huge selection for a day of pleasure and inspiration, or to pick up some plants. Most of my clients are in the Fairfax and greater Washington area, but I am currently living out west below Front Royal, VA on the Shenandoah mountainside - wonderful views. cascio.offsite@gmail.com