The ipod shuffle is the first ipod that uses flash memory, meaning it is ideal for those who particpate in physical activities such as running as you can not damage the hard disk. There are two different types of shuffles- the first generation and the second generation. The first generation shuffle only weighs 20 grams meaning it is no burden to carry and can store up to 240 songs at random (hence the name shuffle). As it has a USB connector, it can be also be used as a flash drive. The first generation shuffle only comes in white.
The second generation shuffle has been named 'the world's smallest mp3 player' and has all the same features as the first generation shuffle apart from a built in USB connector (still has flash drive feature via included dock). It also comes in 9 different colours which increases the consumer's choice.
In my opinion, the second generation shuffle proves a much better buy, as it is smaller and more versatile with the exact same features.