I myself own a Sandisk Sansa e250, which is quite good, plays photos, videos, music and FM radio.
I uploaded an episode of something or other to it one day, when I found out it splits the video into separate parts about 10 minutes each.
I think it's meant for music videos, not 30-minute tv shows.
As for the battery, its as good as whatever player that was that actually did last the 20 hours as promised.