What're your summers like, Nancita? What exposure does the porch have and what do you use it for? For our front, north-facing walk-in porch I chose a traditional Charleston green, a regional color which is almost black, for a deep, cool look that would harmonize with the lighter green foliage all around, but we were forced to go light on the porch we sit out on because the summer sun on even a medium green here will make it too hot to walk on. I noticed on browsing the web that current front porch floor colors are typically deplorably limited and boring, but I would think any color that was considered generally acceptable for a front door could be used in a somewhat muted or darkened, or perhaps lightened, version without raising eyebrows. For back deck color, you're outside but still separated from "nature" while sitting on it. Would you like a look that reinforces the shelter feeling (interior-style elements and colors carried outside), or would you like to embrace nature more and feel more as if you were sitting in a park or woods, only without your chairs sinking in? :)

I would post this in design dilemmas as well. When I have a hard time making a decision and there are many choices, I only choose between two at a time. Start with your siding first, A against B, A against C, C against D, etc. After I made a final siding choice, if I couldn't find a trim color that works with it, I'd eliminate that siding color and I'd start the siding process again. It's hard for us to suggest colors without seeing your choices.

My concern with a black and white scheme and the look you are going for is this: the typical "modern farmhouse" or other white with black window houses generally have pretty balanced massing (if not nearly symmetrical on some elevation), and a uniform window size and placement. Your house, a 1970s rancher has a functionalist window placement, sizing and placing the windows based on the inside needs first, rather than the facade, and the windows are kind of small compared to wall area, which is also typical of the style of house you have. I am not sure but I think a pure black/white scheme would emphasize some things in not such a good way. I would consider reversing the scheme in a way and doing a grey house with white trim, unless you are going to enlarge the existing windows and add more. Or a white house with grey trim, not something so high contrast.

not sure the rest of the house looks like but I assume you added the siding to add accent I would stain if it diesnt fit the look to stain. I would stain a heavier body stain semi solid off white or a greige stain