Apple- Inside Blog.

With all that music at your fingertips, you may never want to stop listening. Lucky thing your iPod plays audio for up to 20 hours.⁽²⁾ Or, if you’d rather watch, you can feast your eyes on movies and TV shows for up to six-and-a-half hours.⁽³⁾

Pack light

It might be a miracle. Otherwise, it’s hard to explain exactly how 30GB of storage⁽⁴⁾ can fit into an iPod that’s over 30% thinner than the previous fourth generation. Or how an 80GB iPod can be the same size as the 60GB model before it. However it happened, it means you can carry your entire music collection — plus a nice selection of video — absolutely everywhere you go. And a 60% brighter, more vibrant display gives your album art, photos, and video extra oomph.

Search and enjoy

Finding what you want to hear among 20,000 songs could be quite a chore — unless you have an iPod. A new interface lets you search your iPod using the patented Click Wheel. And if you’re a fan of live albums, classical works, or anything that sounds best when it’s continuous, iPod supports gapless playback that seamlessly transitions from one song to another.