When I am piecing a quilt I use an off white thread. When I quilt I use a white quilting thread. (I want to see my quilting) I don't use black or navy colors usually. I love calico fabric. I love the small designs and the fact it is 100% cotton. If I was rich I would have calico everywhere and would never use any thing with it except 100% cotton. However when I applique I always use the closest color or thread that matches the fabric. You can't see many of my stitches when I applique. The best thing to do if you love quilting DO IT YOUR WAY. I have seen some quilts that were really awful quilting but you didn't see that as much as you did the perfectly matched seams and wonderful points. There is no such thing as a bad quilt. Someone gave me a ragged quilt that had been used in moving and abused (I wanted to cry) I restored it best as I could, quilts have hearts you know.