I made two loaves of sourdough boule yesterday, but they had very little sourdough taste. I used Peter Reinhardt's recipe in his book, "The Bread Baker's Apprentice". It uses about a cup of starter to make a preferment, then preparing the dough the following day. The loaves were beautiful, had a wonderful texture and crumb, but not any real sourdough flavor. (BTW, this was my second time making sourdough bread).
The first time I made sourdough, I used a different recipe that called for starter, but also commercial yeast. It was a good bread and had sourdough flavor, but I was looking for more.
I used the same starter in both, which is a homemade starter. I also don't use it very often, I keep it in the fridge, and when I go to use it, I warm it up to room temp and feed it.