I don't think the Segway even compares. It was a big deal, in part because of the secrecy, but the mass market appeal remains limited. I want an iPhone, will probably get an iPhone, and still I feel like I have iPhones coming out of my ears already. It's a fascinating marketing and media study, to be sure.
Apple put the iPhone completely out of my court when they tied it only to Cingular/ATT. The only wireless provider who can provide a reliable signal in the hills where I live is Verizon, and until the iPhone talks Verizon, I'm not interested. Besides, from Verizon, I get genuine high-speed data transfer - I was listening to a discussion of the iPhone on NPR's Forum this morning, and I gather the Cingular wireless network is just a tad slow.