Cesar reported today Zune can play music for 13 hours straight, with Wifi on! This is pretty impressive because it is the same as on a video iPod with a slightly smaller screen (2.5 inches) and no Wifi on it.

Cesar goes on: We got to 14 hours (wireless off) based on the following conditions: a single length average album of 128 kbps ripped WMA songs, played on repeat; with the EQ (equalizer) setting set to “none”; the default volume setting (i.e. not turning volume up or down); the backlight timer set to 1 second; and with no other activity (like viewing pictures, navigating, etc.) going on.

And how about Video and photos? Cesar says Zune can take up to 4 hours of video playback or photo viewing.

So never mind the batteries in the photo, you will not need these!

Read the full article:  http://www.zuneinsider.com/2006/10/battery_life.html