In his latest keynote, Steve Jobs unveiled the new iteration to the iPod Nano line. The fourth generation of iPod Nanos comes in 9 different colors and sport curved aluminum cases and glass screens. The new form factor, unlike the stocky third generation, is elongated body similar to the 2nd generation of Nanos.

Steve Jobs also presented the new interface, dubbed as the “Genius playlist interface,” that goes into coverflow mode when the gadget is rotated and goes into shuffle mode when shaken (hopefully this can be overrode when you are on a thread mill or in a bumpy ride).

The battery life of the new iPod Nano lasts for 24 hours when playing songs and 4 hours when watching videos.

The new Nano comes in 2 variants: one with 8GB capacity which costs $150 and the other with 16GB storage which costs $200.

The keynote also unveiled the new iPod touch, a new version of iTunes and a new firmware upgrade of the iPod touch.