I don't know how other people setup their iPod playlists for their commute. This is how I do it.
1. I subscribe to many podcasts. Too many.
2. When my rss feeds are refreshed in the morning, I go to the 'Recently Added' playlist.
3. I subscribe to many feeds that are only 1-2 minutes long (The Onion, 60 second science). I give these 4 stars.
4. The casts that I want to keep as a priority, I give 3 stars. It is likely I will listen to these today.
5. The filler-casts or ones I want to save for later in the week, get 2 stars.
I have created a playlist of all podcasts that have a playcount of zero, sorted (descending) based on the number of stars. If I don't get to all of the podcasts that day, they are on the list for the next day.
It is a quick way to set things up in the morning.