I recently picked up a creative zen vision w media play from circuit city.  It was on clearance since they were not longer going to carry the item.  This worked out well for me since I wanted this particular model.  I chose it over others because I only wanted to play videos and not surf the web with it.  I am still reviewing the battery performance so I can only say that the reviews mentioned this was one of the better models.  What is great about this unit is the large 4.3″ screen.

The one problem I had with the unit is the formats supported.  It mentions support of a large variety of videos formats where in reality it only supports a small subset.  It relies on a windows based converter to change into the correct format, however this process has yet to succeed for me.   I really do not care as I figured out the format it needs, and I just use linux tools like ffmpeg and mplayer to convert the video to that format.

What is really great, is that I can download all these lectures from online sites and load them right up into the machine.   It has given me something productive to do on the train to work.