The Dark Gray Canvas basemap is released (see the blog announcing it, with URLs to the basemap itself and its component base layer and reference layer).
So, how do you use it well? Can you simply swap it in, and everything magically works with your map's main subject matter?
Maybe. But just in case your thematic map isn't quite looking like you'd hoped on Dark Gray Canvas, read this blog and this blog from the map's designer, Andy Skinner. He explains how colors work well on top of a dark map, with lots of examples.
Share your maps that use Dark Gray Canvas back to this thread, so others can benefit from your work!