My usual plan is to have the binding fairly dark to serve as a frame for the entire quilt. Of course a number of other factors go into what actually happens! Most often the deciding factor is how much fabric I have of whatever color that I might want to use. If there is enough of several, then I just lay the finished top on each of the possibilities and pick the one that I decide I like best. I tend to consider my binding the final (often - only) border.