On October 12, 2005, Apple announced at the "One more thing..." [14] event, the fifth-generation iPod, which featured the ability to play MPEG-4 and H.264 video with resolutions of up to 480 x 480 (maximum pixel count of 230,400) and 320 x 240 (maximum pixel count of 76,800), respectively (videos purchased from the iTunes Music Store are limited to 320 x 240.) Some users have reported the ability to play widescreen resolutions up to 640x360 using MPEG-4 and 400x192 using H.264 (total pixel count is equal to the stated maximums) The new models are available in 30 and 60 GB capacities and are priced the same as the previous generation at $299 and $399 USD, respectively. However, the 30 and 60 GB versions differ in body thickness, the 30 GB version being slightly thinner.

It has a 65,536 color (16-bit) screen, [15] with a 320 x 240 QVGA transflective TFT display, and is able to display video on an external TV via the AV cable accessory [16], which plugs into the headphone minijack and splits into composite video and audio output connectors with RCA jacks. It can also display video on an external TV using the iPod AV or S-video cables with the iPod Universal Dock [17], however video watched on a TV is often of poor quality due to the fact that iPod video can only play videos up to 480x480. The screen size is now 2.5" (6.35 cm) diagonally, 0.5" larger than the previous iPod. It is also 30% thinner than the previous full-size iPod.

The reported battery life for the 30 GB is 14 hours and for the 60 GB is around 20 hours. Watching movies reduces that amount to 2 and 3 hours respectively.

The click wheel design is the same as the previous generation, but is marginally smaller than before. The new click wheel is completely flat, unlike older models where the center button is slightly rounded. Apple has stopped using the click wheels used in the fourth generation iPod and iPod mini from their previous supplier, Synaptics Inc of San Jose, CA, and now uses an in-house solution.

The headphone jack has been moved from the center of the top to the right of the top, while the hold switch has been moved to the left side of the top. Gone from the fifth-generation iPod is the remote control accessory port, previously found beside the headphone port, meaning that accessories such as the Griffin iTrip will no longer work. Griffin has, however, released a new version of the iTrip for the new iPod, which mounts to the dock connector on the bottom of the unit.

Like the iPod nano, it comes in two colors, white and black, and it features the World Clock, Stopwatch, and Screen Lock applications. In addition, the earphones plug is smaller.

The fifth-generation iPod also comes with a thin slip case, most likely in response to many complaints concerning the iPod nano's easily scratchable surface. Apple has also discontinued the inclusion of an AC adapter and FireWire cable. One must purchase one separately in order to charge it from the AC. The fifth-generation iPod no longer supports file transfers via FireWire, but still supports charging using FireWire.

Other notable improvements include the reduction of minor audio defects, such as hard drive noise being heard through the headphone jack, as well as an increase in recording quality to 44.1 kHz stereo, 22.05 kHz mono. A third-party addon will still be required in order to record audio on the iPod, as it was in previous generations.

On October 12, 2005 Apple reintroduced the Harry Potter collectible iPod along with the update of the iPod line. The new Harry Potter iPod retains the laser engraved Hogwarts crest on back of the device and is sold with the "complete Harry Potter" (the first 6 books in the Harry Potter series). The capacity of the iPod was increased to 30 GB from the previous 20 GB. The price point remains the same as the fourth-generation model.

From: http://en.wikipedia.org/wiki/Ipod#Models