I'm often asked how much memory should an iPod for classroom use have. In the typical classroom, the 120GB iPod classic is overkill. Whenever I can, I ask to see classroom iPods to check how much storage is actually used. In most cases, it's one or two gigabytes. Now, in classrooms that are using iPods to store dozens of videos from TeacherTube, YouTube, and United Streaming, several gigabytes are used. In almost all cases, 8GB is going to be plenty. The 8GB iPod nano retails for $150.
What about the iPod touch? The lowest-priced touch is $230 with 8GB of storage. Besides storing audio and video, that 8GB also has to have room for all of those wonderful software applications from the App Store. I have my iPod touch loaded up with hundreds of songs (1.7 days worth), several podcasts, 1.9 hours of high quality video, and 571 photos. Besides all that media, I have 89 apps installed.
As you can see from the Capacity Graphs above, I still have plenty of room on my iPod touch. And surprising to me is that although I have it loaded with 7 screens of apps, they only take up 604MB. That's an average of 6.8MB per app. And since you can only load up to 9 screens of apps (for a total of 148), a touch full of apps only needs about 1GB (1,006MB) reserved for that. That leaves 6GB remaining for media, which I think is plenty for classroom use. For personal use, 6GB may not be enough to hold your entire music collection--but I'm talking school use.
Unlike many handhelds and MP3 players, iPods don't have an expansion slot. So when you purchase an iPod, you have to make sure you get the right amount of memory. If you don't get enough gigabytes, you will have to carefully manage what gets put on the iPod through iTunes. If you get too capacity, you end up overpaying (a 16GB iPod touch is $300 and 32GB is $400).
If you want to see how full your iPod is, connect it to your computer. In Tunes, click the iPod in the Devices sidebar. On the Summary tab, scroll down to the bottom of the screen. You'll see a Capacity Graph like mine above. Click the graph to change among number, size, and length of items.