I'd love to be the kind of runner who doesn't need to listen to an iPod, but I'm not. On my weekly long runs I listen to NPR programing that I've downloaded...they have a podcast of stories involving religion which are usually worth a listen. I've also discovered a Bill Moyers podcast on Faith and Reason in which he interviews writers. Yesterday my run was a little over 2 hours so I got to listen to 2 episodes, one of which featured American writer Mary Gordon who is a devout Catholic. Here's a great quote from that interview:
"Faith without doubt is either a kind of nostalgia, or addiction"
I totally value doubt in faith.