I'm using gPodder before every flight to download latest podcasts (currently subscribed to Monocle Weekly and 37signals).
The only improvement that comes to mind immediately is automatic downloads that would happen on the background. That'd mean I would be able to remove "fetch podcasts" from my before-trip checklist.

Very good feature set and design. Nice collection of sample podcasts. Some usability improvements are needed to reduce the number of taps, that's why in my opinion it is not a five-star application (yet).