According to engadget, with the wireless off, Microsoft Zune will have around 12 hours of music playback (at 128Kbps) or 3.5 hours of video playback. If we compare it with 30BG iPod (which has 14 hours of music playback or 4 hours of video playback) it is little on the lesser side.

This little lesser battery life of Zune is due to it bigger screen size. Lets hope and see whether Microsoft fixes this up before retailing the Zune.