I took my recently rejuvenated Scroll Wheel iPod on a coast-to-coast plane trip for work. I loaded some podcasts on it (they show up in Playlists-Podcasts by the way, all lumped in together, so don’t try to have dozens of podcasts on an original iPod) and took it with me. I listened to Deadly Manners for most of the 5-hour plane ride and it still showed 4 bars out of 4 for battery. I then left it in my luggage for a couple of days (didn’t charge it) and listened to music for 4 or 5 hours on the way back home. After getting home, it still showed 4 bars of battery life!
So I haven’t done a comprehensive battery test on it (run it all the way down), but 8 hours of playback and still reporting a full battery? I’m pretty happy. Plus I had the bonus of getting off the plane with a fully charged iPhone since I just left it off during the ride.