More sour starter, and seeding starter with commercial yeast
I know, I said commecrial yeast and sourdough in the same sentence. Don't hit me! :)
My first successful starter came from the recipes and techniques in Bread Alone. The first step involved using a pinch of IDY (less than 1/16 tsp) along with the water and stone ground rye.
I've since used a bit of this starter to seed a white flour starter. Both starters are very healthy, and produce wonderful loaves (see my recent pictures in the photos forum). I never added any commercial yeast after the pinch at the start.
My only complaint is they add almost no sour flavor to the bread. I was thinking that the strain of yeast in IDY hasn't allowed the local yeasties to take over, but the sour flavor is from the bacteria, not the yeast, right?