The iPod Nano range was updated last week so there will not be many user reviews yet.
http://www.apple.com/uk/ipodnano/
The previous version was highly successful, selling 10 million units. Some people reported problems with the screen and casing scatching, but the new ones are made from aluminium not plastic. They also come in a range of bright colours.
Here is a previous thread about file formats
http://www.theanswerbank.co.uk/How-it-Works/Qu estion290669.html
You can download iTunes for free and play with it. You do not need an iPod to checkout the software. Here is the link
\http://www.apple.com/uk/itunes/download/