Julian, well said as usual. Let me add a couple quick thoughts while they are fresh in mind. One is that unexpressed needs or undocumented requirements can be thought of as expectations. To use your analogy, I may not know I need vitamin C, but I expect to live in a healthy way. It is our jobs as BAs to turn those expectations or unstated needs into the usable form you describe, namely requirements.
The other thought revolves around value. Like you I am passionate about it, but I usually talk in terms of benefits. Your post hits the right note about the iPod feature (sorry no pun intended) being less important than the benefit or value of the experience of listening to my music whenever I want and happen to have my iPod with me. A 'Gucci' bag may have status benefits for the owner over a knock-off. Benefits are central to solid business cases, which I've been speaking and writing about a lot lately.
BTW, the CCM was a big hit at this year's BASSA conference in Cape Town. I attended a session in which the presenter did a great job representing it (and cited your articles).