First of all, gorgeous quilt you made! Kudos! Give yourself a pat, and all that stuff.
That being said, I would go with the darkest blue. I think it would frame the quilt nicely. Since the bindings get worn more, I think a light color would show dirt more. The dark blue will still set the quilt off nicely, but at least hide some of the dirt that is just going to happen with wear.
JMHO!
M