As I've mentioned recently, I'm a podcast listener. Most of my listening is done while I'm at work, but if I'm doing a treadmill workout, I listen to them there too. (I tend not to use headphones outside, to hear more of what's going on around me.)
Most weeks, I end up downloading more podcasts then I can listen to during work hours, so I have some "leftover" ones to listen to on the treadmill. For some reason, Science Friday from NPR usually ends up being what I'm listening to there - Ira Flado quizzing scientists about various topics.
Podrunner running mixes.
I downloaded the latest mix (The Fire Inside) and gave it a listen during my progression run. It was a good dance mix at 147 beats per minute. In retrospect, that was pretty good for a warm-up but probably could have been faster for the speed sections of that run. The music isn't 100% my style, but might make a nice change once in a while. I'll have to be more careful picking the BPM that's right for what workout I'm doing...
One cool feature of Podrunner is another set of mixes they have up, the Podrunner Intervals - designed to work specifically with the Couch to 5K program ( as well as an 8K and 10K program.) If you're getting started on one of those training schedules, those are worth a look.