Each individual model of the iPod has a different hard drive capacity. The 16GB, or gigabyte, versions of the iPod Nano and iPod Touch have significantly less storage capacity than the iPod Classic and the largest version of the iPod Touch. These devices can still hold a large amount of media, however, especially for a portable device.
The number of songs available depends on the average length of the songs in your library, as well as the bitrate at which your songs were ripped to your hard drive. The default bitrate for most audio software is 192 kilobytes per second (KBps), although songs ripped at 320 KBps have an audio transfer and clarity of sound that is closer to that of a compact disc. A 16GB iPod can be filled with nearly 3,500 songs ripped at 192 KBps, with an average length of three minutes. With music files ripped at the higher quality 320 Kbps, however, the device can only hold about 2,200 songs of the same average length.
For the 16GB iPod Touch (as well as the iPhone, iPod Classic and other sizes of the iPod Touch), the iTunes Store offers television episodes, movies and other videos for download. These videos are available in high-definition and standard definition resolutions, with a significant distinction in file size. In general, HD videos are nearly three times the size of standard definition videos. The 16GB iPod Touch can hold just over 16 hours (or 32 half-hour episodes) of standard definition video, while the same iPod can only hold about six hours of high definition video.
Also unavailable on the 16GB iPod Nano, applications purchased from iTunes's App Store are significantly different sizes, contingent upon the function and graphics of the app itself. For example, a game might require anywhere between two and 50 megabytes (MB) of space on your iPod Touch. Some games with 3-D environments need even more space. Simple apps for other utilities, however, might use less than 1MB of space on your device. Because of this large variation in size, the number of apps you can fit onto your iPod Touch is primarily determined by how much space is occupied by other files.
iPod Nano or iPod Touch?
Deciding which 16GB will better suit your storage needs simply depends on how you plan to use the device. If you want an iPod for portable videos and to take advantage of the App Store, you want an iPod Touch (and you might even consider an upgrade in size). If you only want an iPod for music listening on the go, try an iPod Nano with the added benefit of an FM radio tuner and a built-in pedometer for tracking your exercise while you listen.