Background Help....Please!

I'm doing a Kaleidoscope Quilt Along at:
http://dontcallmebetsy.blogspot.com/
With more pictures to view at:
http://www.flickr.com/groups/kaleidoscopeqal/

I am using up some blue/green, green/yellow scraps and I originally thought, to get away from the white I often use, that I would use the Kona Ash...how daring is that? Not really that much removed from white but I thought "I like gray and turquoise/aqua together" Well, as you can see from the picture it is very boring and it might as well be white.

The quilt will be scrappy, these pieces are only representational, but basically it will consist of blue/green, yellow/green scraps. 
Now I need your help....I have dark gray Kona, Black Kona and Navy Kona in my stash...yes, I want to use from my stash. Subtle differences I know. Which do you prefer? The black is dramatic but I'm leaning toward the navy.  I was going to cut the solid tonight but now I'm going to wait for your input.  Thank you!

I will allow myself to buy something fun/new for the binding and backing. Next month! Remember, I'm on a budget  (except when my husband is out of town says my sister! tee hee!)

Enjoy!
Toni