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From Wikipedia:

The September 2006 revision featured a brighter display, longer video battery life, and a music search function. 60 GB was discontinued.
 
primarily battery life

battery life is much improved

also brighter display and gapless playback
 
The new ones allow gapless playback. I don't think this was backwards compatible with a firmware update. Correct me if I'm wrong.

OK, I think I will. :)
My 5G iPod from November 2005 has gapless playback, and so does my brother's old nano. The firmware update also added the brightness control and the scroll-by-letter thing.
 
OK, I think I will. :)
My 5G iPod from November 2005 has gapless playback, and so does my brother's old nano. The firware update also added the brightness control and the scroll-by-letter thing.

not to my old nano... that's one feature I'd really love on it.
 
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