Slate. It's the hot new color. The best thing is slate is not just one color. While you can describe it in general as a dark gray, that's really an injustice to the beauty and versatility of this color which can have green, blue, or even purple hues. The color in the picture is Benjamin Moore's Mohegan Sage # 2138-30.
(As many of you know, Benjamin Moore is my favorite paint manufacturer. A good paint dealer can take any color and match it to another manufacturer.)