The iPod mini in either 4GB or 6GB is a great value. Not only does it hold 1,000-1,500 songs-- more than most people even have-- it is tiny, light, and the battery really does last roughly as long as Apple claims. In addition, the human interface element has been professionally developed and perfected to be a totally peerless system that is easy to use. Updating is a snap. Has some great features that will "wow" you. As soon as I used the touch wheel for the first time, I knew it was the product I'd been waiting for. With an advertised battery life of 18 hours, mine made it to 15 hours on the first overnight charge with normal use-- skipping around, adjusting volume, with backlight, etc. Long enough for any international flight.
While the interface is simple and intuitive, it comes at a price: lack of fine control over playback and other options. For example, you can't modify playlists, change play order, or make new playlists without connecting to a computer. It's true that you can make an "on the go" playlist (see documentation), but it takes some effort.