That is wicked, wicked, wicked!!! You're house is going to look so awesome come halloween, I cannot wait to see the followups and how everything looks together.
I LOVE the dark look of it! Buuut, I think it would look great if it had just a bit of color. Like a dry brushing of a dark purple on the house, just hit the edges of the shingles with a medium grey dry brush. Dry brush the steps in a light grey, the molding and trim in a greyish white, then lightly wash the door and tree with a dark brown. Just don't cover up too much of the black!
or, or, or, I know! Barely dry brush the whole thing in a greyish white, it'll keep the monotone color, won't cover too much of the black, but will really make all the great features pop.
If at any time you have put on too much color, just come back and 'antique' in black, it'll be perfectly gloomy