Sherwin Williams' "Agreeable Gray" is arguably the most popular color of the last few years. It offers enough contrast to make white trim really "pop" and can trend either gray or beige depending on the lighting and surroundings, so it's a great neutral. I am considering it for the main wall color in our home. The other two colors I am considering are "Repose Gray" (another warm gray) and "Light French Gray" (a cooler gray.) I've got samples of all and will study them under the LED lights once they're installed before making a decision. (Side note: you can now get peel and stick samples of colors of just about any color you'd ever want to visualize on your wall without damaging the surface or having to paint and repaint from samplize.com)
I stumbled across some designers that are using interior doors to add a splash of color that's easy to repaint if your taste changes and I loved the idea. (Check out the Creativity Exchange). I love Benjamin Moore's Aegean Teal, but it's too dark. A shade lighter (Colorado Gray) is softer and more suitable. I painted the inside of an exterior door and both sides of an interior door in the rental house that we're in (with permission, of course), just to be certain that I loved it. I decided that it's a nice accent for the inside of the exterior doors, but I will leave the interior doors white.
Our doors will be the Masonite "Winslow" three panel doors like the one below (though I'm not doing barn doors - just normal swinging doors and a few pocket doors.) The house below is one that our company built. When I saw them in person, I loved them. As a side note, this home also has Agreeable Gray walls and white trim with aged bronze door hardware.
