I'm not sure iPhones are a sensible option at present - not enough memory to store that much and the batteries run down quite fast.
But iPods - that's a different matter. I listen to a lot that way - especially before 10 a.m. when I'm home - no danger of disturbing the neighbours.
Judging from the massive pre-Xmas advertising campaign on the exterior of the buses here, the iPod is still alive, tho' perhaps in need of a boost. I'd thought it had died the death, as my daughters, who once seemed addicted to it, never mention it now and do all their listening on their phones. I suspect they're very typical of the 18 to 30-ish age group, judging by my observations as a bus rider.