Using a cylinder instead of a cone is getting me to deal more with the ellipses. Having the extra ellipse on the bottom makes me think more clearly about the ellipse that is wrapping around the middle and has highlighted some gaps in my understanding.
P sage on the ConceptArt forums suggested I take a look at moatddtutorials. I especially liked this one The Basics: what they mean
I liked what he said about switching back and forth between the cubes and the cylinders and using the two ideas to support each other. It made me think about these two approaches to breaking down the figure. There's a Luca Cambiaso drawing from the mid 1500's at the beginning of Robert Beverly Hale's Drawing Lessons from the Great Masters that shows a block breakdown really nicely, and Walt Reed's The Figure: The Classical Approach to Drawing and Construction has really nice cylindrical breakdowns.
The Circles and Ellipses feel better, easier, more natural to me, but the cubes provide valuable information in dealing with perspective that I don't think I can get from the ellipses alone.
I'm reading about childhood drawings in Drawing on the Right Side of the Brain and Edward's has this to say - "One of the most basic scribbling movements is a circular one, probably arising from the way that shoulder, arm, wrist and fingers work together. A circular movement is a natural movement - more so, for instance, than the movement required to draw a square. (Try both on a piece of paper, and you'll see what I mean)" pg 67 Maybe that accounts for my preference.