My furnishings are all tans from last house......or should I go with white walls?

That's the kicker right there.

You have two options. Ignore the color of the furniture and base the whole-house wall color on the finish selections only. Or.

Consider the color of the furniture to help inform the wall color and don't put 100% of that work on the new house selections.

A third option (I know I said two) is go with a full spectrum paint color because it will be more forgiving in terms of shifting and blending vs. a more static *regular* paint color.

A go-to for me in the lane of color you're wanting is Ellen Kennon's Mushroom.

I am wondering if I can pull this look off with my charcoal floor and blue gray cabinets if I use this SW Modern Gray paint? What do you think? Close?

Have you looked at Alabaster?

Different rooms are going to show differently with lighting by day then by night. Best thing to do is select a couple of the colors you favor and get a couple of poster board cut in to 4's and leave the outer edge of the poster board white so your eyes don't play tricks on you. That is really the only way you will know if it turns green, blue or other in your particular space.

I do love Shoji White. Shoji White is the perfect warm white with a gray undertone; it looks beautiful with wood or metal finishes. Yet, you need to see how it looks in your space even though it's under construction. If you have lighting in then you can see your picks placed on a few different walls so you know they don't change AM to PM lights on and off.

Modern Gray is very pretty and if you find it a hint too dark given SW sells larger sample cans you can have them lighten it 25% (25% will be a very, very little bit lighter or you can do 50%) after testing it by taking the can back to them and telling them to lighten it. Concerned it might be cold, but do love the color. If you google Modern Gray by SW you will see it changes a lot in different rooms.

My objection to Alabaster is that the counters and backsplash are going to be so white that those white's are too close in color to Alabaster too give any contrast.

Yep, exactly. And if you don't get the chroma - the amout of grayness - right in the paint color, the walls could make the back splash look dull and muddy. Or vice versa, the back splash will make your wall color look dull and muddy. Using whites from the same hue family takes a little finessing and you definitely can't do that considering the stage of building you're in. I just wrote another blog post about Alabaster today.

Yes, no matter what one thinks any room is going to be different with any single neutral paint. Glad you are going to sample a few in your own home in your own lighting.