This a helpful posting. "Need" was something I didn't focus much on until I read John Truby's book, which does a good job of distinguishing the protagonist's want from his or her need.

bookworm676, the Want and Need 'lens' has been out and about for decades, and like you, I find it quite helpful. I like to take it one step further which I'll get into in another post, hopefully in the next few days: Conscious Goal and Unconscious Goal.